diff --git a/application/api/controller/Common.php b/application/api/controller/Common.php
index 4039587..08121d7 100755
--- a/application/api/controller/Common.php
+++ b/application/api/controller/Common.php
@@ -325,6 +325,93 @@ class Common extends Api
         return $key;
     }
     
+    /**
+     * 注册验证码图片 - 生成算术验证码并返回base64图片
+     * GET /api/common/captcha
+     */
+    public function captcha()
+    {
+        $a = mt_rand(1, 20);
+        $b = mt_rand(1, 20);
+        $operators = ['+', '-'];
+        $op = $operators[array_rand($operators)];
+        if ($op == '-' && $a < $b) {
+            // 确保减法结果非负
+            $tmp = $a; $a = $b; $b = $tmp;
+        }
+        $answer = ($op == '+') ? ($a + $b) : ($a - $b);
+        $text = "{$a} {$op} {$b} = ?";
+
+        // 生成唯一key标识本次验证码
+        $captcha_key = md5(uniqid(mt_rand(), true));
+
+        // 将答案存入缓存（使用ThinkPHP缓存，5分钟过期）
+        cache('captcha_' . $captcha_key, strval($answer), 300);
+
+        // 生成验证码图片
+        $width = 200;
+        $height = 60;
+        $img = imagecreatetruecolor($width, $height);
+
+        // 背景色
+        $bgColor = imagecolorallocate($img, 240, 244, 250);
+        imagefilledrectangle($img, 0, 0, $width, $height, $bgColor);
+
+        // 干扰线
+        for ($i = 0; $i < 5; $i++) {
+            $lineColor = imagecolorallocate($img, mt_rand(100, 200), mt_rand(100, 200), mt_rand(100, 200));
+            imageline($img, mt_rand(0, $width), mt_rand(0, $height), mt_rand(0, $width), mt_rand(0, $height), $lineColor);
+        }
+
+        // 干扰点
+        for ($i = 0; $i < 50; $i++) {
+            $dotColor = imagecolorallocate($img, mt_rand(100, 255), mt_rand(100, 255), mt_rand(100, 255));
+            imagesetpixel($img, mt_rand(0, $width), mt_rand(0, $height), $dotColor);
+        }
+
+        // 文字颜色
+        $textColor = imagecolorallocate($img, mt_rand(10, 80), mt_rand(10, 80), mt_rand(10, 80));
+
+        // 使用内置字体绘制文字
+        $fontSize = 5; // imagestring内置字体最大5
+        $textWidth = imagefontwidth($fontSize) * strlen($text);
+        $textHeight = imagefontheight($fontSize);
+        $x = ($width - $textWidth) / 2;
+        $y = ($height - $textHeight) / 2;
+        imagestring($img, $fontSize, $x, $y, $text, $textColor);
+
+        // 输出为base64
+        ob_start();
+        imagepng($img);
+        $imgData = ob_get_clean();
+        imagedestroy($img);
+
+        $base64 = 'data:image/png;base64,' . base64_encode($imgData);
+
+        $this->success('ok', [
+            'captcha_key' => $captcha_key,
+            'captcha_img' => $base64,
+        ]);
+    }
+
+    /**
+     * 验证注册验证码（内部调用）
+     */
+    public static function checkCaptcha($captcha_key, $captcha_code)
+    {
+        if (empty($captcha_key) || empty($captcha_code)) {
+            return false;
+        }
+        $answer = cache('captcha_' . $captcha_key);
+        if ($answer === false || $answer === null) {
+            return false;
+        }
+        $result = (trim($captcha_code) === trim($answer));
+        // 验证后立即删除，防止重放
+        cache('captcha_' . $captcha_key, null);
+        return $result;
+    }
+
     /**
      * 生成随机key secrit
      */
diff --git a/application/api/controller/User.php b/application/api/controller/User.php
index 796a140..3c358dd 100755
--- a/application/api/controller/User.php
+++ b/application/api/controller/User.php
@@ -141,21 +141,23 @@ class User extends Api
         $mobile = $this->request->post('mobile',"");
         $m_prefix = $this->request->post('m_prefix',"");
         $code = $this->request->post('code');
+        $captcha_key = $this->request->post('captcha_key', '');
         $pwd2 = $this->request->post('pay_pwd');
         $referral_code = $this->request->post('referral_code', '');
 
+        // 验证图形验证码（替代邮箱/短信OTP）
+        if (!$captcha_key || !$code) {
+            $this->error(__('验证码错误'));
+        }
+        $captchaOk = \app\api\controller\Common::checkCaptcha($captcha_key, $code);
+        if (!$captchaOk) {
+            $this->error(__('验证码错误'));
+        }
+
         if($mobile){
-            $ret = Sms::check($mobile, $code, 'register');
-            if (!$ret && $code!=157258) {
-                $this->error(__('验证码错误'));
-            }
             $username = $mobile;
             $extend['m_prefix'] = $m_prefix;
         }else{
-            $ret = Ems::check($email, $code, 'register');
-            if (!$ret && $code!=157258) {
-                $this->error(__('验证码错误'));
-            }
             $username = $email;
             $extend['m_prefix'] = "";
         }