StaaS (Storage as a Service) has been envisioned as the next generation archi-tecture of IT enterprise. Enterprise, individual end users move more and more important information to outsourced data centers, where the data may be misappropriated in the ma-licious model. Moreover, users hesitate to store data in the cloud storage because of network fluctuation. Security and availability become the main conc of cloud storage. This paper, to address these issues, presents an architecture of High Available cloud Stor-age Gateway(HASG). In our design, data file is divided into implicit, redundant blocks by file fragment algorithm. Part of these blocks, which are stored on different designated cloud servers, can be used to reconstruct original file. Additionally, dynamic service provider se-lection algorithm and redundant block mecha-nism for file updating is proposed to effectuate cost and bandwidth savings and accelerate data accessing. Experimental results illustrates that our design enhanced security of cloud storage and improved data access efficiency.developed rapidly in last decade. Meanwhile, the increasing network bandwidth and reliable yet flexible network connections make it even possible that clients can now subscribe high quality services of data and software that re-side solely on remote data centers. Increased flexibility and budgetary savings driving companies to store data on Cloud storage for archiving, backup, and even primary storage of files[1,2]. With increasing of data on re-mote Servers, where the management of the data and services may not be fully trustworthy, user pay more attention on data security. Some Data leakage events, such as iCloud data inter-ception, downtime of Amazon’s S3[3], aggra-vate the concing to protect privacy stored on Cloud Storage.