The invention relates to a cartridge disassembling device and a disassembling method thereof. The cartridge disassembling device comprises a cartridge-loading device, a heating device and a control device, wherein an electric control part of the cartridge-loading device and the electric control part of the heating device are both electrically connected with the control device; and the heating device is arranged on the exterior of the cartridge-loading device and is used for heating a to-be-treated cartridge entering into the cartridge-loading device, so that a primer mixture in a primer of the to-be-treated cartridge can reach an ignition point under the effect of high temperature. The cartridge disassembling device has the beneficial effects that the to-be-treated cartridge fills the cartridge-loading device, and then the heating device is utilized to heat and the primer mixture in the primer of the to-be-treated cartridge can reach the ignition point under the effect of high temperature, so that the primer mixture on the cartridge can be disassembled; in the whole disassembling process, the correct position and direction of the cartridge need not be deliberately guaranteed; multiple cartridges can be simultaneously disassembled; the whole disassembling process is low in time consumption; the whole structure is simple; and the maintenance is convenient.