The invention discloses a method for testing the conductivity of a grounding grid. The existing DC (direct current) power supply is replaced by a 30kHz AC (alternating current) power supply; and compared with existing DC measurement, a voltage signal is measured more easily, and a measurement result is more reliable. With high frequency, due to the mutual inductance between a current lead and the grounding grid, the current on the grounding grid is mainly gathered near the grounding point and the current lead and hardly flows to other areas of the grounding grid, and thus the current distribution is very concentrated. The measurement result of the method mainly indicates the conduction condition of the grounding body near the grounding point and the current lead so as to realize local measurement of the grounding grid and reflect the situation of local corrosion and breakage of the grounding grid. Since the current flows in from one point of the grounding grid and out from another point and mainly flows in a grounding conductor and rarely flows into the soil around, a test result experiences little influence of the historical change of soil resistivity, and the conduction and corrosion conditions of the grounding grid can be judged by comparing the test result with the historical test result.