就像您链接的示例一样，但不是使用wp_insert_post() 您使用：wp_update_post() 所以你的表格变成：

<?php
$post_to_edit = get_post($post_id); 
?>

<!-- edit Post Form -->
<div id="postbox">
    <form id="new_post" name="new_post" method="post" action="">
        <p>
            <label for="title">Title</label><br />
            <input type="text" id="title" value="<?php echo $post_to_edit->post_title; ?>" tabindex="1" size="20" name="title" />
        </p>
        <p>
            <label for="description">Description</label><br />
            <textarea id="description" tabindex="3" name="description" cols="50" rows="6"><?php echo $post_to_edit->content; ?></textarea>
        </p>
        <p>
        <?php 
            $cat = wp_get_post_terms( $post_to_edit->ID, \'category\');
            wp_dropdown_categories( \'show_option_none=Category&tab_index=4&taxonomy=categoryselected=\'.$cat[0]->term_id);
        ?>
        </p>
        <p>
            <label for="post_tags">Tags</label>
            <input type="text" value="<?php the_terms( $post_to_edit->ID, \'post_tag\', \'\', \', \', \'\' ); ?>" tabindex="5" size="16" name="post_tags" id="post_tags" />
        </p>
        <p align="right"><input type="submit" value="Publish" tabindex="6" id="submit" name="submit" /></p>
        <input type="hidden" name="action" value="f_edit_post" />
        <input type="hidden" name="pid" value="<?php echo $post_to_edit->ID; ?>" />
        <?php wp_nonce_field( \'new-post\' ); ?>
    </form>
</div>

<!--// edit Post Form -->

if( \'POST\' == $_SERVER[\'REQUEST_METHOD\'] && !empty( $_POST[\'action\'] ) &&  $_POST[\'action\'] == "f_edit_post" && isset($_POST[\'pid\'])) {
    //get the old post:
    $post_to_edit = get_post((int)$_POST[\'pid\']); 

    //do you validation
    //...
    //...


    // Add the content of the form to $post_to_edit array
    $post_to_edit[\'post_title\'] = $_post[\'title\'];
    $post_to_edit[\'post_content\'] = $_post[\'description\'];
    $post_to_edit[\'tags_input\'] = array($_post[\'post_tags\']);


    //save the edited post and return its ID
    $pid = wp_update_post($post_to_edit); 


    //set new category
    wp_set_post_terms($pid,(array)($_POST[\'cat\']),\'category\',true);

}