Provided is a server of a checking system based on a millimeter wave security inspection device, connected to a security inspection instrument through a switching system, the server includes a memory and a processor, the memory stores instructions, and the instructions, when executed by the processor, cause the processor to: receive a scanned image of an object and an ATR image interpretation result of the object from the security inspection instrument, wherein the ATR image interpretation result is obtained by the security inspection instrument performing an automatic threat recognition (ATR) image interpretation on the scanned image, and perform a manual inspection task on the object and perform an image interpretation task on the scanned image according to a working mode, wherein the working mode indicates whether the checking system is provided with a manual inspection station and an image interpretation station.