how to create a page.tpl.php without $page['content']? The page.tpl.php of my website shouldn't contain &lt;?php print render($page['content']); ?&gt; because it is only set of blocks. The problem is I'm not able to insert comment form into node pages of a website which its page.tpl.php hasn't &lt;?php print render($page['content']); ?&gt; . what shall I do?
You have asked simple question &amp; there is very simple answer for that --

Yes, you can create page.tpl.php without &lt;?php print render($page['content']); ?&gt;. You just have to remove this snippet from the TPL file &amp; it will work.

But then you have explained your issue about comment. 

So if you go through the structure of tpl files at theme, you will understand that &lt;?php print render($page['content']); ?&gt; is responsible to print node.tpl.php &amp; that one contains &lt;?php print render($content['comments']); ?&gt;.

So without fetching the things of node.tpl.php you won't get comments. Anyway, how a comment can be associated to a page when there is no node.