The invention discloses a vehicle-mounted intelligent grounding detection system. The vehicle-mounted intelligent grounding detection system comprises a signal collection module, a simulation signal processing module, an analog-digital conversion module and a digital signal processor. The vehicle-mounted intelligent grounding detection system can intelligently judge that whether an electric power special test car is effectively grounded or not, automatic protection can be achieved if not, and accordingly an electrifying switching on test cannot be achieved; the test safety of the electric power special test car is improved; the safety of test personnel and the test equipment is effectively protected.