diff --git a/build.gradle.kts b/build.gradle.kts
index 3404b05..08bca36 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -37,8 +37,6 @@ repositories {
 }
 
 dependencies {
-    implementation("org.springframework.boot:spring-boot-starter-data-elasticsearch")
-    implementation("org.springframework.boot:spring-boot-starter-data-redis")
     implementation("org.springframework.boot:spring-boot-starter-validation")
     implementation("org.springframework.boot:spring-boot-starter-web")
     implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
@@ -50,17 +48,23 @@ dependencies {
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core-jvm:$kotlinxCoroutinesVersion")
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-jdk9:$kotlinxCoroutinesVersion")
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactor:$kotlinxCoroutinesVersion")
+    // kotlin 反射
     implementation("org.jetbrains.kotlin:kotlin-reflect")
     // sa-token 安全认证框架
     implementation("cn.dev33:sa-token-spring-boot3-starter:1.35.0.RC")
     // jimmer 持久层框架
     implementation("org.babyfish.jimmer:jimmer-spring-boot-starter:0.7.104")
     ksp("org.babyfish.jimmer:jimmer-ksp:0.7.104")
-//    developmentOnly("org.springframework.boot:spring-boot-docker-compose")
     implementation("org.postgresql:postgresql")
     // Kafka
     implementation("org.springframework.kafka:spring-kafka")
+    // redis
+    implementation("org.springframework.boot:spring-boot-starter-data-redis")
+    // 腾讯云COS
+    implementation("com.qcloud:cos_api:5.6.133")
+    // configuration processor
     annotationProcessor("org.springframework.boot:spring-boot-configuration-processor")
+    // test
     testImplementation("org.springframework.boot:spring-boot-starter-test")
 }
 
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/AicsKnowledgeBaseBackendApplication.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/AicsKnowledgeBaseBackendApplication.kt
index 80446ef..12dbfe2 100644
--- a/src/main/kotlin/cn/edu/hfut/auto/knowledge/AicsKnowledgeBaseBackendApplication.kt
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/AicsKnowledgeBaseBackendApplication.kt
@@ -1,11 +1,13 @@
 package cn.edu.hfut.auto.knowledge
 
 import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.boot.context.properties.ConfigurationPropertiesScan
 import org.springframework.boot.runApplication
 import org.springframework.web.bind.annotation.RequestMapping
 import org.springframework.web.bind.annotation.RestController
 
 @SpringBootApplication
+@ConfigurationPropertiesScan
 @RestController
 class AicsKnowledgeBaseBackendApplication {
     @RequestMapping("/hello")
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/config/TencentAPIConfig.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/config/TencentAPIConfig.kt
new file mode 100644
index 0000000..0ccbe20
--- /dev/null
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/config/TencentAPIConfig.kt
@@ -0,0 +1,28 @@
+package cn.edu.hfut.auto.knowledge.config
+
+import com.qcloud.cos.COSClient
+import com.qcloud.cos.ClientConfig
+import com.qcloud.cos.auth.BasicCOSCredentials
+import com.qcloud.cos.region.Region
+import org.springframework.boot.context.properties.ConfigurationProperties
+import org.springframework.context.annotation.Configuration
+import org.springframework.stereotype.Component
+
+@Configuration
+class TencentAPIConfig
+
+@Component
+class COSClientWrapper(tencentProperties: TencentProperties) : COSClient(
+    BasicCOSCredentials(tencentProperties.secretId, tencentProperties.secretKey),
+    ClientConfig(Region(tencentProperties.cosRegion))
+) {
+    val bucketName = tencentProperties.bucketName
+}
+
+@ConfigurationProperties(prefix = "tencent")
+data class TencentProperties(
+    val secretId: String,
+    val secretKey: String,
+    val cosRegion: String,
+    val bucketName: String
+)
\ No newline at end of file
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/controller/KnowledgeController.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/controller/KnowledgeController.kt
index 10f2500..9d40e7a 100644
--- a/src/main/kotlin/cn/edu/hfut/auto/knowledge/controller/KnowledgeController.kt
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/controller/KnowledgeController.kt
@@ -1,10 +1,8 @@
 package cn.edu.hfut.auto.knowledge.controller
 
 import cn.dev33.satoken.annotation.SaCheckRole
-import cn.edu.hfut.auto.knowledge.entity.Knowledge
-import cn.edu.hfut.auto.knowledge.entity.KnowledgeDraft
-import cn.edu.hfut.auto.knowledge.entity.KnowledgeFileAttribute
-import cn.edu.hfut.auto.knowledge.entity.by
+import cn.edu.hfut.auto.knowledge.config.COSClientWrapper
+import cn.edu.hfut.auto.knowledge.entity.*
 import cn.edu.hfut.auto.knowledge.entity.rpc.FileTicket
 import cn.edu.hfut.auto.knowledge.entity.vo.KnowledgeFileUploadVO
 import cn.edu.hfut.auto.knowledge.exception.BusinessError
@@ -12,6 +10,7 @@ import cn.edu.hfut.auto.knowledge.exception.ErrorCode
 import cn.edu.hfut.auto.knowledge.repository.KnowledgeFileAttributeRepository
 import cn.edu.hfut.auto.knowledge.repository.KnowledgeRepository
 import cn.edu.hfut.auto.knowledge.util.fileSuffix
+import com.qcloud.cos.model.ciModel.job.DocHtmlRequest
 import kotlinx.coroutines.future.await
 import org.apache.kafka.common.KafkaException
 import org.babyfish.jimmer.kt.new
@@ -33,7 +32,8 @@ const val UPLOAD_FILE_TOPIC = "upload_file"
 class KnowledgeController(
     private val kafkaTemplate: KafkaTemplate<String, Any?>,
     private val knowledgeRepository: KnowledgeRepository,
-    private val knowledgeFileAttributeRepository: KnowledgeFileAttributeRepository
+    private val knowledgeFileAttributeRepository: KnowledgeFileAttributeRepository,
+    private val cosClientWrapper: COSClientWrapper
 ) {
 
     @GetMapping("/{knowledgeId}")
@@ -84,4 +84,20 @@ class KnowledgeController(
             return this
         }
     }
+
+    @GetMapping("/{knowledgeId}/preview/external")
+    suspend fun getExternalPreviewKnowledgeUrl(@PathVariable knowledgeId: UUID): String {
+        knowledgeRepository.findNullable(knowledgeId, Knowledge.BRIEF_FETCHER)
+            ?.knowledgeFileAttribute
+            ?.takeIf { it.externalPreviewable }
+            ?.let {
+                val request = DocHtmlRequest().apply {
+                    bucketName = cosClientWrapper.bucketName
+                    dstType = DocHtmlRequest.DocType.html
+                    objectKey = "${it.id}.${it.suffix}"
+                }
+                return cosClientWrapper.GenerateDocPreviewUrl(request)
+            }
+            ?: throw BusinessError(ErrorCode.RESOURCE_NOT_FOUND)
+    }
 }
\ No newline at end of file
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/KnowledgeFileAttribute.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/KnowledgeFileAttribute.kt
index 5f00ff2..4d9073c 100644
--- a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/KnowledgeFileAttribute.kt
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/KnowledgeFileAttribute.kt
@@ -31,6 +31,7 @@ interface KnowledgeFileAttribute {
     val notes: List<Note>
 
     companion object {
+        val EXTERNAL_PREVIEWABLE_SUFFIXES = listOf("pdf", "ppt", "pptx", "doc", "docx", "xls", "xlsx")
         val BRIEF_FETCHER = newFetcher(KnowledgeFileAttribute::class).by {
             allScalarFields()
             tags {
@@ -38,4 +39,7 @@ interface KnowledgeFileAttribute {
             }
         }
     }
-}
\ No newline at end of file
+}
+
+inline val KnowledgeFileAttribute.externalPreviewable: Boolean
+    get() = suffix in KnowledgeFileAttribute.EXTERNAL_PREVIEWABLE_SUFFIXES
\ No newline at end of file
diff --git a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/rpc/FileTicket.kt b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/rpc/FileTicket.kt
index 882bbe3..1f9b336 100644
--- a/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/rpc/FileTicket.kt
+++ b/src/main/kotlin/cn/edu/hfut/auto/knowledge/entity/rpc/FileTicket.kt
@@ -1,15 +1,18 @@
 package cn.edu.hfut.auto.knowledge.entity.rpc
 
 import cn.edu.hfut.auto.knowledge.entity.KnowledgeFileAttribute
+import cn.edu.hfut.auto.knowledge.entity.externalPreviewable
 import org.apache.commons.codec.digest.Sha2Crypt
 import java.time.LocalDateTime
-import java.util.UUID
+import java.util.*
 
 data class FileTicket(
     val ticket: String,
     val id: UUID,
     val md5: String,
-    val size: Long
+    val size: Long,
+    val externalPreviewable: Boolean,
+    val suffix: String
 ) {
     constructor(knowledgeFileAttribute: KnowledgeFileAttribute, md5: String): this(
         buildString {
@@ -19,10 +22,12 @@ data class FileTicket(
                 append(LocalDateTime.now())
             }
         }.let {
-              Sha2Crypt.sha256Crypt(it.toByteArray())
+            Sha2Crypt.sha256Crypt(it.toByteArray())
         },
         knowledgeFileAttribute.id,
         md5,
-        knowledgeFileAttribute.size
+        knowledgeFileAttribute.size,
+        knowledgeFileAttribute.externalPreviewable,
+        knowledgeFileAttribute.suffix
     )
 }
diff --git a/src/main/resources/application-dev.yml b/src/main/resources/application-dev.yml
index a3438fd..5d717bf 100644
--- a/src/main/resources/application-dev.yml
+++ b/src/main/resources/application-dev.yml
@@ -30,4 +30,10 @@ logging:
   config: classpath:log4j2-dev.xml
 
 aics:
-  max-permission-level: 3
\ No newline at end of file
+  max-permission-level: 3
+
+tencent:
+  secret-id: AKIDSlvvhEYfYBetvYzCBvhJrDLGwNbcR2B7
+  secret-key: kHZigS3UkqlY8WiuypXM3ZwCHA0iHepp
+  cos-region: ap-nanjing
+  bucket-name: aics-1300085057
\ No newline at end of file
diff --git a/src/main/resources/application-prod.yml b/src/main/resources/application-prod.yml
index 1624083..2c98006 100644
--- a/src/main/resources/application-prod.yml
+++ b/src/main/resources/application-prod.yml
@@ -29,4 +29,10 @@ logging:
   config: classpath:log4j2-prod.xml
 
 aics:
-  max-permission-level: 3
\ No newline at end of file
+  max-permission-level: 3
+
+tencent:
+  secret-id: AKIDSlvvhEYfYBetvYzCBvhJrDLGwNbcR2B7
+  secret-key: kHZigS3UkqlY8WiuypXM3ZwCHA0iHepp
+  cos-region: ap-nanjing
+  bucket-name: aics-1300085057
\ No newline at end of file