diff --git a/src/cookies.ts b/src/cookies.ts
index f4c9b7e..f8b6f28 100644
--- a/src/cookies.ts
+++ b/src/cookies.ts
@@ -155,6 +155,7 @@ export class Cookies {
     if (opts.partitioned) {
       if (
         !this.secure ||
+        !userAgent ||
         (userAgent && !this.isPartitionedCompatible(userAgent))
       ) {
         // ignore partitioned when not secure or incompatible clients
@@ -162,6 +163,13 @@ export class Cookies {
       }
     }
 
+    if (opts.priority) {
+      if (!userAgent || (userAgent && !this.isPriorityCompatible(userAgent))) {
+        // ignore priority when not secure or incompatible clients
+        opts.priority = undefined;
+      }
+    }
+
     const cookie = new Cookie(name, value, opts);
 
     // if user not set secure, reset secure to ctx.secure
@@ -213,6 +221,16 @@ export class Cookies {
 
     return this.uaParseResult;
   }
+
+  protected isPriorityCompatible(userAgent: string) {
+    // Chrome >= 81.0.0.0
+    // https://developer.chrome.com/blog/new-in-devtools-81?hl=zh-cn#cookiepriority
+    const result = this.parseChromiumAndMajorVersion(userAgent);
+    if (result.chromium && result.majorVersion) {
+      return result.majorVersion >= 81;
+    }
+    return false;
+  }
 }
 
 const patternCache = new Map();
diff --git a/src/interface.ts b/src/interface.ts
index ad225d9..1b71d85 100644
--- a/src/interface.ts
+++ b/src/interface.ts
@@ -64,10 +64,12 @@ export interface CookieSetOptions {
   signed?: boolean;
   /**
    * a string indicating the cookie priority. This can be set to 'low', 'medium', or 'high'.
+   * only supported in chrome 81+.
+   * https://developer.chrome.com/blog/new-in-devtools-81?hl=zh-cn#cookiepriority
    */
-  priority?: 'low' | 'medium' | 'high';
+  priority?: 'low' | 'medium' | 'high' | 'Low' | 'Medium' | 'High';
   /**
-   * a boolean indicating whether to partition the cookie in Chrome for the CHIPS Update，false by default. 
+   * a boolean indicating whether to partition the cookie in Chrome for the CHIPS Update，false by default.
    * If this is true, Cookies from embedded sites will be partitioned and only readable from the same top level site from which it was created.
    */
   partitioned?: boolean;
diff --git a/test/cookies.test.ts b/test/cookies.test.ts
index fac8d42..5a05c91 100644
--- a/test/cookies.test.ts
+++ b/test/cookies.test.ts
@@ -394,9 +394,48 @@ describe('test/cookies.test.ts', () => {
     assert.ok(cookies.secure);
     assert.ok(cookies1.secure === false);
     assert.ok(cookies2.secure === true);
-  })
+  });
+
+  describe('opts.priority', () => {
+
+    it('should test priority options when ua is empty', () => {
+      const cookies = CreateCookie();
+      cookies.set('foo', 'bar', { priority: 'High' });
+      assert(!cookies.ctx.response.headers['set-cookie'][0].includes('priority=High'));
+    });
+
+    it('should test priority options when ua is chrome low version', () => {
+      const cookies = CreateCookie({
+        headers: {
+          'user-agent': 'Mozilla/5.0 (Linux; Android 4.4.4; SM-G530H Build/KTU84P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.108 Mobile Safari/537.36',
+        },
+      });
+      cookies.set('foo', 'bar', { priority: 'High' });
+      assert(!cookies.ctx.response.headers['set-cookie'][0].includes('priority=High'));
+    });
+
+
+    it('should test priority options when ua is chrome high version', () => {
+      const cookies = CreateCookie({
+        headers: {
+          'user-agent': 'Mozilla/5.0 (Linux; Android 4.4.4; SM-G530H Build/KTU84P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.2987.108 Mobile Safari/537.36',
+        },
+      });
+      cookies.set('foo', 'bar', { priority: 'High' });
+      assert(cookies.ctx.response.headers['set-cookie'][0].includes('priority=High'));
+    });
+  });
 
   describe('opts.partitioned', () => {
+
+    it('should test partitioned options when ua is empty', () => {
+      const cookies = CreateCookie({
+        secure: true,
+      }, { secure: true });
+      cookies.set('foo', 'bar', { signed: true, partitioned: true });
+      assert(!cookies.ctx.response.headers['set-cookie'][0].includes('partitioned'));
+    });
+
     it('should not send partitioned property on incompatible clients', () => {
       const userAgents = [
         'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML%2C like Gecko) Chrome/64.0.3282.140 Safari/537.36',
@@ -494,7 +533,8 @@ describe('test/cookies.test.ts', () => {
       assert(opts.secure === undefined);
       assert(cookies.ctx.response.headers['set-cookie'].join(';').match(/foo=hello/));
       for (const str of cookies.ctx.response.headers['set-cookie']) {
-        assert(str.includes('; path=/; secure; httponly; partitioned'));
+        assert(str.includes('path=/; secure; httponly'));
+        assert(!str.includes('; path=/; secure; httponly; partitioned'));
       }
     });