diff --git a/includes/class-yoone-moneris-api.php b/includes/class-yoone-moneris-api.php
index 32ee23b..3722bab 100644
--- a/includes/class-yoone-moneris-api.php
+++ b/includes/class-yoone-moneris-api.php
@@ -121,22 +121,51 @@ class Yoone_Moneris_API implements Yoone_Moneris_API_Interface {
         if ( empty( $this->store_id ) || empty( $this->api_token ) ) {
             return array( 'success' => false, 'error' => 'Missing Moneris credentials' );
         }
+        // 为避免重复 orderId 导致主机拒绝，生成唯一订单 ID
+        if ( ! function_exists( 'yoone_moneris_unique_order_id' ) ) {
+            require_once __DIR__ . '/utils/orderid.php';
+        }
+        $unique_order_id = yoone_moneris_unique_order_id( $order_id );
         $type = $capture ? 'res_purchase_cc' : 'res_preauth_cc';
         $payload = array(
             'dataKey'   => (string) $token,
-            'orderId'   => (string) $order_id,
+            'orderId'   => (string) $unique_order_id,
             'amount'    => $this->format_amount( $amount ),
             'cryptType' => $this->crypt_type,
         );
-        error_log('【Yoone Moneris API】charge_token 请求：type=' . $type . ' token_len=' . strlen($token) . ' amount=' . $payload['amount'] . ' currency=' . $currency . ' orderId=' . $order_id);
+        error_log('【Yoone Moneris API】charge_token 请求：type=' . $type . ' token_len=' . strlen($token) . ' amount=' . $payload['amount'] . ' currency=' . $currency . ' orderId=' . $unique_order_id . ' (源Woo订单ID=' . $order_id . ')');
         $res = $this->send_moneris_xml( $type, $payload );
         if ( $res['ok'] ) {
             return array(
                 'success'        => true,
                 'transaction_id' => (string) ( $res['receipt']['txnNumber'] ?? '' ),
+                'order_id_used'  => $unique_order_id,
+                'retry'          => false,
             );
         }
-        return array( 'success' => false, 'error' => (string) $res['error'] );
+        // 如果出现系统错误，尝试一次自动重试（更换新的唯一 orderId）
+        $err_msg = isset($res['error']) ? (string)$res['error'] : '';
+        $is_system_error = stripos($err_msg, 'SYSTEM ERROR') !== false;
+        if ( $is_system_error ) {
+            $retry_order_id = yoone_moneris_unique_order_id( $order_id );
+            $payload['orderId'] = (string) $retry_order_id;
+            error_log('【Yoone Moneris API】检测到 SYSTEM ERROR，准备重试一次。新的 orderId=' . $retry_order_id);
+            // 短暂延时，避免立即重复错误
+            usleep(300 * 1000);
+            $res_retry = $this->send_moneris_xml( $type, $payload );
+            if ( $res_retry['ok'] ) {
+                return array(
+                    'success'        => true,
+                    'transaction_id' => (string) ( $res_retry['receipt']['txnNumber'] ?? '' ),
+                    'order_id_used'  => $retry_order_id,
+                    'retry'          => true,
+                );
+            }
+            // 记录重试失败
+            error_log('【Yoone Moneris API】重试仍失败：' . (string) ($res_retry['error'] ?? 'Unknown'));
+            return array( 'success' => false, 'error' => (string) ($res_retry['error'] ?? $err_msg) );
+        }
+        return array( 'success' => false, 'error' => (string) $err_msg );
     }
 
     /**
@@ -195,6 +224,13 @@ class Yoone_Moneris_API implements Yoone_Moneris_API_Interface {
 
         $xml = $this->array_to_moneris_xml( array( 'request' => $body ) );
 
+        // 日志：打印部分已脱敏的 XML 以便排查格式问题（掩码 pan、data_key、api_token）
+        $xml_log = $xml;
+        $xml_log = preg_replace('/<pan>[^<]*<\/pan>/', '<pan>****</pan>', $xml_log);
+        $xml_log = preg_replace('/<data_key>[^<]*<\/data_key>/', '<data_key>****</data_key>', $xml_log);
+        $xml_log = preg_replace('/<api_token>[^<]*<\/api_token>/', '<api_token>****</api_token>', $xml_log);
+        error_log('【Yoone Moneris API】请求 XML（脱敏）前 400 字符：' . substr($xml_log, 0, 400));
+
         $args = array(
             'method'      => $this->http_method ?: 'POST',
             'timeout'     => $this->timeout,
@@ -221,6 +257,8 @@ class Yoone_Moneris_API implements Yoone_Moneris_API_Interface {
 
         // 解析 XML
         $parsed = $this->parse_moneris_xml( $raw );
+        // 打印部分响应原文，便于调试
+        error_log('【Yoone Moneris API】响应原文前 300 字符：' . substr($raw, 0, 300));
         if ( ! $parsed['parsed'] ) {
             error_log('【Yoone Moneris API】XML 解析失败：' . ($parsed['error'] ?? 'Unknown'));
             return array( 'ok' => false, 'error' => 'Parse error: ' . ( $parsed['error'] ?? 'Unknown' ) );
diff --git a/includes/utils/orderid.php b/includes/utils/orderid.php
new file mode 100644
index 0000000..27d026c
--- /dev/null
+++ b/includes/utils/orderid.php
@@ -0,0 +1,33 @@
+<?php
+if ( ! defined( 'ABSPATH' ) ) {
+    exit;
+}
+
+/**
+ * 生成用于 Moneris 的唯一订单 ID（避免重复 orderId 导致主机拒绝）。
+ *
+ * 规则：<原始订单ID>-<毫秒时间戳>-<四位随机数>
+ * 示例：1234-1730835123456-4821
+ *
+ * 注意：Moneris 对 orderId 的长度是有限制的（通常不超过 50 字符）。本实现控制在合理长度范围内。
+ * 如需自定义格式，可在此函数中调整。
+ *
+ * @param int|string $order_id WooCommerce 订单 ID
+ * @return string 唯一订单 ID 字符串
+ */
+function yoone_moneris_unique_order_id( $order_id ) {
+    // 毫秒级时间戳
+    $ms = (int) floor( microtime( true ) * 1000 );
+    // 四位随机数
+    $rand = mt_rand( 1000, 9999 );
+    // 仅保留数字和字母，避免特殊字符
+    $base = preg_replace( '/[^a-zA-Z0-9_-]/', '', (string) $order_id );
+    // 拼接唯一后缀
+    $unique = $base . '-' . $ms . '-' . $rand;
+    // 限长保护（最多 50 字符）
+    if ( strlen( $unique ) > 50 ) {
+        // 若过长，截断前半部分（保留后缀）
+        $unique = substr( $base, 0, max( 1, 50 - ( 1 + strlen( (string) $ms ) + 1 + 4 ) ) ) . '-' . $ms . '-' . $rand;
+    }
+    return $unique;
+}
\ No newline at end of file