diff --git a/src/backend/drivers/github_releases/util.test.ts b/src/backend/drivers/github_releases/util.test.ts
new file mode 100644
index 00000000..0fba3d72
--- /dev/null
+++ b/src/backend/drivers/github_releases/util.test.ts
@@ -0,0 +1,37 @@
+import test from "node:test"
+import assert from "node:assert/strict"
+import { ClientGithubReleases } from "./util"
+
+function clientWith(ghProxy?: string): ClientGithubReleases {
+  return new ClientGithubReleases({
+    repo_structure: "example/repo",
+    ...(ghProxy !== undefined ? { gh_proxy: ghProxy } : {}),
+  })
+}
+
+function proxyOf(additionGhProxy: string | undefined, url: string): string {
+  const client = clientWith(additionGhProxy)
+  // proxy() 为私有方法，测试中通过索引访问
+  return (client as unknown as { proxy: (u: string) => string }).proxy(url)
+}
+
+test("gh_proxy 已配置时为 http(s) 下载链接加代理前缀", () => {
+  const url = "https://github.com/example/repo/releases/download/v1.0.0/app.zip"
+  assert.equal(
+    proxyOf("https://mirror.example.com", url),
+    "https://mirror.example.com" + url,
+  )
+})
+
+test("gh_proxy 未配置时保持原链接不变", () => {
+  const url = "https://github.com/example/repo/releases/download/v1.0.0/app.zip"
+  assert.equal(proxyOf(undefined, url), url)
+  assert.equal(proxyOf("", url), url)
+})
+
+test("gh_proxy 已配置但链接非 http 开头时不加前缀（对齐上游 Go 版语义）", () => {
+  assert.equal(
+    proxyOf("https://mirror.example.com", "/relative/path"),
+    "/relative/path",
+  )
+})
diff --git a/src/backend/drivers/github_releases/util.ts b/src/backend/drivers/github_releases/util.ts
index d3c9ade6..2945ff50 100644
--- a/src/backend/drivers/github_releases/util.ts
+++ b/src/backend/drivers/github_releases/util.ts
@@ -61,8 +61,8 @@ export class ClientGithubReleases {
 
   private proxy(url: string): string {
     const p = this.addition.gh_proxy || ""
-    if (!p || url.startsWith("http")) return url
-    return p + url
+    if (p && url.startsWith("http")) return p + url
+    return url
   }
 
   /** 解析挂载点对应的 org/repo */