废话就不多说了，直接上代码，把下面的代码加入到模板函数functions.php文件中就大功告成了

// 修�WordPress����滤�����Email�����
function chanbee_allow_email_login($username, $raw_username, $strict) {
  if (filter_var($raw_username, FILTER_VALIDATE_EMAIL)) {
    $user_data = get_user_by('email', $raw_username);
    
    if (empty($user_data))
      wp_die(__('<strong>ERROR</strong>: There is no user registered with that email address.'), '����正确');
    else
      return $user_data->user_login;
  }
  else {
    return $username;
  }
}

// 修���������"���"��"�����箱"
function chanbee_change_text() {
  echo '<script type="text/javascript">
                var user_login_node = document.getElementById("user_login");
                var old_username_text = user_login_node.parentNode.innerHTML;
                user_login_node.parentNode.innerHTML = old_username_text.replace(/���/, "�����箱");
      </script>';
}

if (in_array($GLOBALS['pagenow'], array('wp-login.php')) && strpos($_SERVER['REQUEST_URI'], '?action=register') === FALSE && strpos($_SERVER['REQUEST_URI'], '?action=lostpassword') === FALSE && strpos($_SERVER['REQUEST_URI'], '?action=rp') === FALSE ) {
  add_filter('sanitize_user', 'chanbee_allow_email_login', 10, 3);
  add_action('login_footer', 'chanbee_change_text');
}

回过头想想，为什么要输入冗长的email来登录呢？用用户名登录不快捷点吗！？这功能还是给有需求的人用吧。