Abstract: Since the demands of the increasing exploration depths,the high-power induced polarization method is playing an important role in the exploration of the concealed metallic sulfide deposits. During the time domain high-power induced polarization exploration of the Xiyi large-scale concealed Pb-Zn deposit in Baoshan,Yunnan,the authors in this study disclosed that the apparent resistivity values of the overburden tend to be effected by the rainfalls during the dry seasons,and high resistivity shielding phenomena in the overburden would have direct influence on the induced polarization data quality and prospecting effects. In the light of observed results of high-power induced polarization data obtained in different seasons and theoretical analysis and numerical simulation calculations,the seasonal factors are interpreted to have direct influence on both earth resistivity of the overburden and induced polarization exploration. The particular suggestions are drawn to the optimal time selection,i. e. October to December in the induced polarization exploration. The results of research in this study are of important practical meaning for the improvement of exploration effects by using induced polarization method.