I want to truncate Description's field because i put it with 700 charecters and i want to show out only 200 charecters in search result with using template

The problem is, the format used for the links in the search results is the same one as used for normal links (sub site_html_link). So, you would have to create a new routine in site_html.link or site_html_templates.pl (maybe called, sub site_html_search_link) that would format the description the way you want. Then just change the call, &site_html_link, in search.cgi to &site_html_search_link.

I hope this helps.