The invention provides a disk snapshot method applied to a server, wherein a snapshot operating module is installed in a kernel space within a memory of the server. When performing disk snapshot, the server receives a create instruction sent by the snapshot operating module, groups all disk chunks containing data in a hard disk of the server as a volume, divides a disk snapshot storage area in the hard disk for storing the original data of each disk chunks belonged to the volume. When the original data of each disk chunks belonged to the volume need to be modified, the original data were first copied to the disk snapshot storage area, then the original data of the volume were modified into modification data, and Copy-On-Write table is created in a user space within the memory and lookup information is written into the Copy-On-Write table, wherein the lookup information contains the information of which disk chunk of the disk snapshot storage area is the original data stored.