Based on the electrical sounding of Xingji Seismic Station，we used the transform function recursive formula to analyze the resistivity variation caused by the ground water level. The result of the model suggests that the ascent of the ground water level can cause georesistivity to rise，which is consistent with the georesistivity observation in N30°E direction at Xingji Seismic Station，but the geosistivity change in N60°W is opposite to that of N30°E and the amplitude of the annual variation of N60°W is bigger than that of N30°E. That was caused by an excavation pit between the electrode N and the power supply electrode B.