Hy I recently search "stackoverflow" via Google and I saw a perfect description about Stackoverflow. Please how can i do this,since Google doesn't use the meta description tag.
Google uses meta description some times. Usually however it's only if "they" do not find something in the search result which matches the users query "good enough". This can happen if searching for - for example - site names.
This means - you cannot determine what Google will show.
They'll determine it themselves.