The present disclosure is to provide a synchronization method and device for a cloud storage system. The method includes receiving an operation request for a file object initiated by a client; calculating a hash value corresponding to the file object according to the operation request; acquiring the partition which the file object is stored according to the hash value; acquiring corresponding storage devices of each copy of the file object according to the partition which the file object is stored; initiating a write request to the storage devices to store the copies of the file object to the corresponding storage devices; and calculating a new hash value of the partition and transmitting the new hash value to an adjacent storage device. With the synchronization method and device of the present disclosure, it may reduce the network overhead and the synchronization delay.