Pager will come by default in blogs template or not? I am using blogs  module in one of the website. I have created a template file for that, I want to add pager if blog items exceeds that 10. So my question is in that template file how can I use pager. It will display by default or is there any other ways to add pager to that template.
If you are creating a custom template for the blogs created by the blog module you will have a variable called $pager available to you in that template. Wherever you want it displayed you can just add something like this:

 &lt;div id="blog-pager" class="pager"&gt;&lt;?php echo $pager ?&gt;&lt;/div&gt;


If you look in blog.pages.inc you'll see that the "pager" is added to the "$build" render array in each of the menu callback functions defined in that file.