By default, WordPress category permalinks are displayed that way:

http://www.omasters.com/blog/category/categorytitle

As you can see, the category in the url is pretty useless. Here’s how to remove it:
First backup your .htaccess file. Then, open it and append the following line:
RewriteRule ^category/(.+)$ http://www.yoursite.com/$1 [R=301,L]
Once saved, your categories pages will be displayed like this:

http://www.catswhocode.com/blog/wordpress

Better, Solution You can simply use plugin to solve the issue

The Top Level Categories plugin allows you to remove the prefix before the URL to your category page. For example, instead of http://fortes.com/category/work, I use http://fortes.com/work for the address my “work” category. WordPress doesn’t allow you to have a blank prefix for categories (they insert category/ before the name), this plugin works around that restriction.

Download Top Level Categories Plugin

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