I am working on magento one website multiple store, my problem is how to fetch only current store products by search. Because at present after search i get all products which are presne in all stores.
Ok, so you have multiple store views for a single website. By default, products in this case are only limited to the website scope (have a look at the "Websites" section in the product configuration page) and thus cannot be set for a single store view.
What you can do is limit the products based on the category scope. Thus, for your store views define separate scopes for your categories. In addition, you might need to set different anchor values for your categories depending on your desired scope.
Store views are generally used to setup different languages for your store. If you are planning to use store views to e.g. share sessions across different domains you will need to do the above to get your scopes working correctly.