I. Introduction
With the rapid development of knowledge economy, information and energy, substance has been considered as three pillars of modem economy, human kind increasingly emphasis on research and value-added exploitation on information re-sources, and make effort to exploit natural resources. However, there exist several problems such as poor information infra-structure, information standards unconformity and information sharing difficulties. Furthermore, traditional information technologies and network environments are highly difficult to meet the requirements of end-users, and unable efficiently to promote value-added exploitation of government information. In recent two years, cloud computing will be new development area in IT industry. According to a report released from IDC, it predicts that cloud computing service market will increase by 26 percent each year in near four years [1]. Storing will be the fastest in terms of increase speeds among cloud computing services.