The torque multiplier, as a device that generates extra-large torque, is widely used in industries such as aviation, aerospace, and shipbuilding. The multiplier amplifies and transmits input torque via an internal mechanical gear set, that the mechanical wear and increased assembly clearance caused by long-term use will have a certain impact on the accuracy of its output torque value. The development of an on-site calibration device, which measurement range is 200–5000 Nm, and can calibrate coaxial or non-coaxial torque multipliers is introduced in this paper. The device with small volume is easy to move. It is also equipped with intelligent instruments, which can achieve loading and unloading control, automatic recognition of sensors, automatic collection and calculation of output input torque ratio.