The invention designs a dynamic calibration device of a drum reaction braking checkout stand, which mainly consists of a servo force-applying mechanism, a buffering shock absorption mechanism, a force-transmitting beam mechanism, a force-measuring mechanism and a support frame mechanism. The dynamic calibration device mainly aims at solving the problem that the existing calibration device of the drum reaction braking checkout stand can not evaluate the dynamic response of the braking stand. The dynamic calibration device is mounted on the drum reaction braking checkout stand for constituting a closed loop control system of force, thereby providing the force value which changes according to an ideal standard force value curve for calibration of the braking stand, comparing the standard force value curve with a measured force value curve which is measured by a force-measuring sensor of the braking stand and passes through a filter-amplifier circuit, evaluating the dynamic response quality of the braking checkout stand and realizing the dynamic calibration.