In order to find out the Yuqiao reservoir dam leakage area and its causes，using high density resistivity method detecting the resistivity distribution in the 93m range of three sections of 0+356，1+130 and 1+605.The results show that the low resistivity bodies exist near the three sections are leakage zones.The detection results and the analysis results of dam seepage pressure monitoring data are basically consistent，verify the reliability of the high density resistivity method.