一：

PHPMailer sdk 文件中有个设置默认编码的位置：

vendor/phpmailer/phpmailer/src/PHPMailer.php

二：

实际业务代码中：

require '/sdk/PHPMailer/vendor/autoload.php';$mail = new PHPMailer(true);try {//Server settings$mail->Charset='UTF-8';//$mail->SMTPDebug = SMTP::DEBUG_SERVER;                      //Enable verbose debug output$mail->isSMTP();                                            //Send using SMTP$mail->Host       = '';        //Set the SMTP server to send through$mail->SMTPAuth   = true;                                   //Enable SMTP authentication$mail->Username   = '';               //SMTP username$mail->Password   = '';         //SMTP password$mail->SMTPSecure = PHPMailer::ENCRYPTION_SMTPS;            //Enable implicit TLS encryption$mail->Port       = '';          //TCP port to connect to; use 587 if you have set `SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS`//Recipients$mail->setFrom('smtp_sender_email', 'smtp_sender_name'); //Change your setting message//$mail->addAddress('joe@example.net', 'Joe User');     //Add a recipient$mail->addAddress($email);               //Name is optional// $mail->addReplyTo('info@example.com', 'Information');// $mail->addCC('cc@example.com');// $mail->addBCC('bcc@example.com');//Attachments// $mail->addAttachment('/var/tmp/file.tar.gz');         //Add attachments// $mail->addAttachment('/tmp/image.jpg', 'new.jpg');    //Optional name//Content$mail->isHTML(true);                                  //Set email format to HTML$mail->ContentType = 'text/html; charset=utf-8';$mail->Subject = ''; //邮件标题$mail->Body    = '';  //邮件内容//$mail->AltBody = 'This is the body in plain text for non-HTML mail clients';$status=$mail->send();if($status){return true;}return false;} catch (Exception $e) {return false;}