尝试此代码（可能有效），但我不确定原因不测试：

function amin_show_expire(){
  global $wpdb;
  $result = $wpdb->get_results("SELECT * FROM wp_posts WHERE post_type = \'CUSTOM\' AND post_status = \'publish\'");
  if( !empty($result)) foreach ($result as $a){
      $show_time = get_the_time("Y-m-d", $a->ID );
      $show_time=date("Y-m-d", strtotime("+1 years", strtotime($show_time)));
      if ( $show_time < date("Y-m-d")){//compare 1 year after post with current time
          $my_post = array();
          $my_post[\'ID\'] = $a->ID;
          $my_post[\'post_status\'] = \'draft\';
          wp_update_post( $my_post );
      }
  } // end foreach
}

add_action( \'init\', \'amin_show_expire\' );