我写了一个small plugin 就在不久前。它钩住了\'save_post\' 如果没有标题集，则将前20个字符作为标题：

add_action( \'save_post\', \'t5_fix_empty_title\', 11, 2 );

/**
 * Fills an empty post title from the first words of the post.
 *
 * @param  int    $post_id      Post ID
 * @param  object $post         Post object
 * @return void
 */
function t5_fix_empty_title( $post_id, $post )
{
    if ( ( defined( \'DOING_AUTOSAVE\' ) && DOING_AUTOSAVE )
        or ! current_user_can( \'edit_post\', $post_id )
        or ! empty ( $post->post_title )
        or empty ( $post->post_content )
        or wp_is_post_revision( $post )
    )
    { // Noting to do.
        return;
    }

    // Remove all tags and replace breaks whith white space.
    $no_tags = wp_strip_all_tags( $post->post_content, TRUE );

    // The post content contains just markup.
    if ( \'\' === $no_tags )
    {
        return;
    }

    $length = apply_filters( \'t5_fix_empty_title_length\', 20 );
    $words  = preg_split( "/\\s+/", $no_tags, $length, PREG_SPLIT_NO_EMPTY );
    array_pop( $words );

    $title = implode( \' \', $words );
    // Add a no break space and an ellipsis at the end.
    $title = rtrim( $title, \'.,!?…*\' ) . \' …\';

    wp_update_post( array ( \'ID\' => $post_id, \'post_title\' => $title ) );
}