posts from a specific category on index.php

Working good by this

<?php query_posts($query_string . '&cat=8'); ?>

Code (markup):

But show same post all page /page/2-3-4-5-6/ all page show same post ...Please help me

 

Because you're not looping it. Hence it only shows one post. Put the query inside a loop, and you should be good to go.

Here:
https://wordpress.org/support/topic/display-the-posts-of-one-category-in-a-page-solved

 

Not work

Not work

 

Since you don't show us any of your code, how are we supposed to help? Using a category as the only post criteria for a site is trivial, so if it's not working, you're doing something wrong. It's as simple as that. Start over - by that I mean, start with an existing template file, modify the query for the post-fetch, and see if that works - then, after you've done that, you can start modifying other stuff you need.