diff --git a/src/lib/upload.ts b/src/lib/upload.ts
index 6a3ff62..1666d39 100644
--- a/src/lib/upload.ts
+++ b/src/lib/upload.ts
@@ -7,6 +7,15 @@ function getWorkingDirectory(): string {
   return process.cwd();
 }
 
+function buildUploadPath(type: string, datePath: string): string {
+  const uploadBaseDir = process.env.UPLOAD_DIR || './uploads';
+  return path.join(getWorkingDirectory(), uploadBaseDir, type, datePath);
+}
+
+function buildFilePath(uploadDir: string, fileName: string): string {
+  return path.join(uploadDir, fileName);
+}
+
 export interface UploadOptions {
   maxSize?: number;
   allowedTypes?: string[];
@@ -132,9 +141,8 @@ export async function uploadFile(
     throw new Error('文件内容与声明类型不匹配');
   }
 
-  const uploadBaseDir = process.env.UPLOAD_DIR || './uploads';
   const datePath = getDatePath();
-  const uploadDir = path.join(getWorkingDirectory(), uploadBaseDir, type, datePath);
+  const uploadDir = buildUploadPath(type, datePath);
 
   if (!existsSync(uploadDir)) {
     await mkdir(uploadDir, { recursive: true });
@@ -144,7 +152,7 @@ export async function uploadFile(
   const extension = getFileExtension(file.type);
   const sanitizedOriginalName = sanitizeFileName(file.name);
   const fileName = `${fileId}${extension}`;
-  const filePath = path.join(uploadDir, fileName);
+  const filePath = buildFilePath(uploadDir, fileName);
 
   await writeFile(filePath, buffer);