The utility model relates to a power generator grounding testing device which is characterized in that a conjunction box (3) which matches the power generator is arranged; a first spring conductive probe (4) and a third spring conductive probe (6) are arranged between the conjunction box (3) and a first conductive plastic disc (1); a second spring conductive probe (5) is arranged between the conjunction box (3) and a second conductive plastic disc (2); the first spring conductive probe (4) and the third spring conductive probe (6) elastically contact with the first conductive plastic disc (1); the second spring conductive probe (5) elastically contacts with the second conductive plastic disc (2); the first spring conductive probe (4) is connected with the third spring conductive probe (6) and is connected with an external terminal (15); and the second spring conductive probe (5) is connected with an external terminal (16). The power generator grounding testing device is applied on a power generator and prevents problems of carbon brush lead breakage, contact between a lead and a housing, severe carbon brush wearing, etc.