The paper describes a backup system guaranteeing service non-stop based on IP-SAN network. The system used the Freeze function which provided by the file system and Snapshot technology to ensure the server non-stop during the server disk does backup, and through the Snapshot generation management and Log management to ensure date integrity and consistency of the backup date. The system support cross-platform, heterogeneous network and remote backup, because it is based on IP-SAN network Experiment show that this system has good stability and reliability.