The invention discloses a grounding device shunting vector testing method based on GPS pulse per second(PPS). The grounding device shunting vector testing method is characterized in that a PPS signal provided by a GPS artificial earth satellite is used to provide the same time marks for shunting vector measurement and signal output, and thereafter the phase difference between the measured shunting vector value and the signal output reference voltage value can be calculated synchronously, and therefore the shunting vector value can be calculated. The invention also discloses a grounding device shunting vector testing device. The extra reference voltage lead is not required, and the limitation and the obstruction of the on-site testing environment conditions such as the area of the to-be-tested grounding device and the existence of the barriers can be prevented, and in addition, the on-site electromagnetic interference capability is strong, and the shunting vector values of the inlet wires and the outlet wires can be accurately measured without dismounting various inlet wires and various outlet wires, and therefore the grounding impedance value of the grounding device can be acquired accurately, the transmission distance is long, the signal delay can be prevented, and the workload is small, and in addition, the on-site test and use can be simpler and more convenient.