I dont want to see all the post in father categories

I will reply this for my self, I just look arround for a while and find this: It works OK
I just copy and paste here

hi i post this ‘cos it’s a way to refresh an old post i found on this forum https://www.ads-software.com/support/topic/71767
and some of you may be interested…
Well, the goal is that each category displays only its own posts and not those of its child categories.

here you go:
(this in WP v.2.0.4, line numbers may change in further versions)

open wp-includes/classes.php
just insert // at the very beginning of these lines – or destroy them:
line 473
$whichcat .= get_category_children($cat_array[0], ‘ ‘.$andor.’ category_id ‘.$eq.’ ‘);

line 476
$whichcat .= get_category_children($cat_array[$i], ‘ ‘.$andor.’ category_id ‘.$eq.’ ‘);

line 514
$whichcat .= get_category_children($q[‘cat’], ” OR category_id = “);

You’re done! Code is poetry, as they say!