By integrating the P2P and cloud technology, we proposed a scalable and efficient cloud storage system that is suitable for large-scale data set in the distribute network. In the system, HDFS is used for local storage system, and Chord is used as the P2P overlay network which connects multiple HDFS to serve fast and reliable storage service. Data storing and distribution, as well as the information retrieval of the system is detailed. Through the analysis and evaluation, this system shows better availability and fault tolerance, and is also efficient in data management and querying process.