在wordpress的主题的functions.PHP里面加入这段代码，就会自动创建Meta描述，前提是确保主题中的header.PHP不可用

function create_Meta_desc() {
global $post;
if (!is_single()) { return; }
$Meta = strip_tags($post->post_content);
$Meta = strip_shortcodes($post->post_content);
$Meta = str_replace(array("",""," "),' ',$Meta);
$Meta = substr($Meta,125);
echo "<Meta name='description' content='$Meta' />";
}
add_action('wp_head','create_Meta_desc');