In sensor network a large amount of data need to be collected for future information retrieval. The data centric storage has become an important issue in sensor network.Storage nodes are used in this paper to store and process the collected data. This paper considers the storage node placement problem aiming to place unlimited storage nodes in sensor network to minimize the total energy cost for collecting the raw data and replying queries at the storage nodes. In this paper a strong data access model for placing storage nodes in sensor network is presented.We consider an application in which sensor networks provide real time data services to user. The main aim of this paper is to reduce the cost for raw data transfer,query diffusion, query reply by defining the best location of storage nodes in sensor network.