function comm(){	 
	$p_id = ( $_POST['spd'] );	
	$args = array(
		'posts_per_page' => -1,
		'p' => $p_id
	);
	$yy_query = new WP_Query($args);	
	while ( $yy_query->have_posts() ) {
		$yy_query->the_post();
global $withcomments;
		$withcomments = true;
		 comments_template();		
	}	
 wp_die();
}
add_action('wp_ajax_mycomm', 'comm');
add_action('wp_ajax_nopriv_mycomm', 'comm');

$('.seecomments').click(function(){	
 	$.ajax({ 		
 		url: ajaxurl, 
 		type: 'POST',		
 		beforeSend: (function(){				
					$('.comment_template').html('Загрузка..');
			}),
 		data: ({
 			action: 'mycomm',	
 			spd: send_post_id 			
 		}),
 		success: function(data){ 		 
 			$('.comment_template').html(data);
 		}
 	})
 });

//code...
<div class="seecomments">показать комменты</div>
<script>
	var send_post_id = <?php the_ID(); ?>;
</script>
//code..