代码来自this page 帮我解决了这个问题。

/**
 * Disable the emoji\'s
 */
function disable_emojis() {
 remove_action( \'wp_head\', \'print_emoji_detection_script\', 7 );
 remove_action( \'admin_print_scripts\', \'print_emoji_detection_script\' );
 remove_action( \'wp_print_styles\', \'print_emoji_styles\' );
 remove_action( \'admin_print_styles\', \'print_emoji_styles\' ); 
 remove_filter( \'the_content_feed\', \'wp_staticize_emoji\' );
 remove_filter( \'comment_text_rss\', \'wp_staticize_emoji\' ); 
 remove_filter( \'wp_mail\', \'wp_staticize_emoji_for_email\' );
 add_filter( \'tiny_mce_plugins\', \'disable_emojis_tinymce\' );
 add_filter( \'wp_resource_hints\', \'disable_emojis_remove_dns_prefetch\', 10, 2 );
}
add_action( \'init\', \'disable_emojis\' );
/**
 * Filter function used to remove the tinymce emoji plugin.
 * 
 * @param array $plugins 
 * @return array Difference betwen the two arrays
 */
function disable_emojis_tinymce( $plugins ) {
 if ( is_array( $plugins ) ) {
 return array_diff( $plugins, array( \'wpemoji\' ) );
 } else {
 return array();
 }
}
/**
 * Remove Emoji in WordPress automatically CDN hostname from DNS prefetching hints.
 *
 * @param array $urls URLs to print for resource hints.
 * @param string $relation_type The relation type the URLs are printed for.
 * @return array Difference betwen the two arrays.
 */
function disable_emojis_remove_dns_prefetch( $urls, $relation_type ) {
 if ( \'dns-prefetch\' == $relation_type ) {
 /** This filter is documented in wp-includes/formatting.php */
 $emoji_svg_url = apply_filters( \'emoji_svg_url\', \'https://s.w.org/images/core/emoji/2/svg/\' );
$urls = array_diff( $urls, array( $emoji_svg_url ) );
 }
return $urls;
}