The invention relates to an impact generator grounding device. According to the device, it is achieved that a ground conductor falls or is lifted through the forward and reverse rotation of a steppingmotor, the ground conductor drives a grounding grid to achieve grounding or de-grounding, a shielding plate manual operation is added between the grounding and the de-grounding so that action is moreaccurate and accidental operation is not generated, thereby achieving effects of automatic grounding and de-grounding; the trouble of requiring manual grounding after the existing power frequency pressure test is eliminated, the safety problems of forgetting grounding and incomplete grounding are avoided, the test safety is improved, and the personal safety of an experimenter is protected.