A system of creating logical volume and method thereof is used to solve the problems such as creation steps are complicated, a space of storage medium is wasted and the number of snapshots to be created is limited. An available logical volume space and a timestamp storage area are allocated in the logical volume according to space allocation algorithm. According to original data and data amended at subsequent time point in the logical volume, copy-on-write operation is sequentially performed on the amended data in the logical volume to create a timestamp corresponding to the time point. The timestamp of the corresponding time point is stored in the timestamp storage area. A storage medium offset address pointer is created to record writing position of the copy-on-write operation of the corresponding time point. And the pointer is stored in the storage medium to serve as index information of address of each timestamp.