In this paper, the authors used the spectrum of IP method to evaluate the IP anomaly with central gradient array for a Pb-Zn-Ag deposit in western Henan Province. V8 multifunctional electrical workstation using the device of 9-channel axial dipole-dipole was employed to collect data. Based on the principle of "from the known to the unknown", the authors summarized the geophysical prospecting indicators which have the combined characteristics of high charge rate, low resistance transition zone, medium time constant and low frequency correlation coefficient. According to the data of geology and mineral resources, the composite IP anomalies characterized by "high—gradient belt (low resistance)—medium—low" were classified and evaluated, and the prospecting target areas were delineated. According to the prospecting target areas, the drilling verification was arranged. The drilling results show that the positioning in the target area of classⅠanomalies led to the discovery of a large-sized concealed orebody in the depth, thus achieving good application effect.