The invention relates to a calibration device for a three-dimensional force measuring platform, which aims at overcoming the defect that the current force calibration device cannot carry out simultaneous force calibration of three directions on a flat plate type three-dimensional force measuring platform and a convex plate type three-dimensional force measuring platform according to the using needs, and providing a device for carrying out comprehensive and simultaneous orthogonal calibration on the force measuring sensor of the three-dimensional force measuring platform. The device can calibrate the two kinds of three-dimensional force measuring platforms with different appearances. The device is composed of a weight tray assembly, a counter-force plate and spoke type pressure sensor assembly and a three-dimensional force measuring platform calibration device foundation platform assembly, wherein the weight tray assembly is put on the three-dimensional force measuring platform, the counter-force plate and spoke type pressure sensor assembly is connected with the three-dimensional force measuring platform and is fixed by a bolt, and the three-dimensional force measuring platform is connected with the three-dimensional force measuring platform calibration device foundation platform assembly and is fixed by the bolt. The weight tray assembly is composed of a channel steel welding frame and a leg cushion block, and the leg cushion block is connected with the channel steel welding frame through the bolt.