diff --git a/server/src/main/java/cn/keking/web/controller/OnlinePreviewController.java b/server/src/main/java/cn/keking/web/controller/OnlinePreviewController.java
index 666e322..2b79eb8 100644
--- a/server/src/main/java/cn/keking/web/controller/OnlinePreviewController.java
+++ b/server/src/main/java/cn/keking/web/controller/OnlinePreviewController.java
@@ -25,9 +25,12 @@ import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
 import org.springframework.web.client.HttpClientErrorException;
 
+import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
+import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.List;
 
@@ -49,6 +52,7 @@ public class OnlinePreviewController {
     private static final String URL_PARAM_FTP_PASSWORD = "ftp.password";
     private static final String URL_PARAM_FTP_CONTROL_ENCODING = "ftp.control.encoding";
     private static final String URL_PARAM_FTP_PORT = "ftp.control.port";
+    private static final String LOCAL_FILE_ROOT = "/home/img";
 
     private final FilePreviewFactory previewFactory;
     private final CacheService cacheService;
@@ -82,6 +86,8 @@ public class OnlinePreviewController {
             String errorMsg = String.format(BASE64_DECODE_ERROR_MSG, "url");
             return otherFilePreview.notSupportedFile(model, errorMsg);
         }
+        // 优先检查本地文件，本地存在则直接使用，避免从公网下载大文件
+        fileUrl = checkLocalFile(fileUrl);
         FileAttribute fileAttribute = fileHandlerService.getFileAttribute(fileUrl, req);
 
         highlightall= KkFileUtils.htmlEscape(highlightall);
@@ -287,4 +293,31 @@ public class OnlinePreviewController {
         cacheService.addQueueTask(fileUrls);
         return "success";
     }
+
+    /**
+     * 检查本地是否已有该文件，若有则返回本地文件路径，避免从公网重复下载
+     *
+     * @param fileUrl 解码后的文件URL
+     * @return 本地文件路径（如果存在），否则返回原始URL
+     */
+    private String checkLocalFile(String fileUrl) {
+        if (fileUrl == null || (!fileUrl.startsWith("http://") && !fileUrl.startsWith("https://"))) {
+            return fileUrl;
+        }
+        try {
+            URL url = new URL(fileUrl);
+            String path = url.getPath();
+            if (path != null && !path.isEmpty()) {
+                String decodedPath = URLDecoder.decode(path, StandardCharsets.UTF_8);
+                File localFile = new File(LOCAL_FILE_ROOT, decodedPath);
+                if (localFile.exists() && localFile.isFile()) {
+                    logger.info("本地文件存在，使用本地文件：{}", localFile.getAbsolutePath());
+                    return "file://" + localFile.getAbsolutePath();
+                }
+            }
+        } catch (Exception e) {
+            logger.warn("检查本地文件失败，url：{}", fileUrl, e);
+        }
+        return fileUrl;
+    }
 }
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