This paper describes the electrical prospecting work for groundwater water in the igneous rock area of Nigeria, Africa, and summarizes characteristics of electrical sounding curves of groundwater in that area. It is shown that the branch tailrace tunnel of the resistivity rises at 45°, the turning point corresponding to AB/2 is larger than or equal to 38 m, and the turning point of the resistivity curve is less than 30 m，with obvious induced polarization rate anomalies.