The invention discloses a three-directional force calibration device and method for a TBM (Tunnel Boring Machine) hob. The characteristics lie in that a standard force sensor is fixed on a sensor base, a pressure head is fixed at the bottom of the standard force sensor, and a calibrated TBM hob holder is fixed on a lower connecting plate. When calibration is performed, a hemispherical holder mounting block is installed at an original rolling part of the holder, and the sensor base drives the pressure head to press downward so as to apply a vertical force to the hemispherical holder mounting block; when calibration is performed on a rolling direction force, an upper connecting plate and a fixed-angle inclined block can be installed at the lower part of the pressure head, the inclined block presses downward so as to be capable of apply a force to the hemispherical holder mounting block, and the force can be decomposed into a vertical force and a rolling direction force; and when calibration is performed on a lateral force, the inclined block below a mounting plate can be enabled to rotate by 90 degrees so as to apply a force to the hemispherical holder mounting block, and the force can be decomposed into a vertical direction force and a lateral force, an output signal of a strain bridge circuit in the corresponding direction on the holder is compared with an output signal of the standard force sensor, and a relation coefficient of stress and strain of the holder is calculated.