How can i get this structure ?
I'am not totally sure about this but I think that firstly you have to submit a site map to google webmaster tools and also your website has to be popular with a lot of visitors to have that structure!
Links like that appear by themselves, at the whim of Google, and you can't control it—except that you can easily lose them if you restructure your site. Links like that start to appear if your site has been online for a while.
Thanks for helpful suggestion.Is there any Google related tool where we have to make changes in our site's data or we have to registered for this kind of structure?Please suggest me if there any......Thanks!!!!
Just make sure that your site has a clear structure with good and consistent internal links, so that it is clear what the main sections/pages are, and Google will figure it out automatically ... if it decides your site is important and popular enough.
In regards to your question, they are actually called Sitelinks and as mentioned you cannot control it and it is really up to Google. For more info on Google Sitelinks and enhancing your chances the probability of it showing underneath you site on serps, here below is the article on GoogleWebmasterTools that describes it in more detail.
Keep in mind that Google will only show sitelinks for results when they think they'll be useful to the user and according to Wikipedia Google adds them through its own secret automated algorithms.
Google usually just do it for larger sites. It's not fully in your control but if you make sure all your pages are structured properly and you have a decent sitemap you may stand a chance in the future. Sites like the one shown usually have very clean sitemaps, google picks up on this and shows it in the searches. Also it's usually only very large sites and sites which have been on the web for 10+ years which get this treatment unfortunately.