简单的解决方案是将这段代码粘贴到主题函数中。php文件：

add_action(\'wp_head\',\'keywords_and_desc\');
function keywords_and_desc(){
    global $post;
    if (is_single()||is_page()){
        if(get_post_meta($post->ID,\'my_keywords\',true) != \'\') 
            echo    \'<meta content="\'.get_post_meta($post->ID,\'my_keywords\',true).\'" name="keywords">\';
        if(get_post_meta($post->ID,\'my_description\',true) != \'\') 
            echo    \'<meta content="\'.get_post_meta($post->ID,\'my_description\',true).\'" name="description">\';
    }
}

或者您可以使用一个非常轻量级且简单的插件，名为Simple Meta Tags