Abstract: This paper introduces the working principle of high density resistivity method and analyzes its advantages as compared with the traditional leakage hidden trouble detection. One test was carried out on dam shoulder leakage detection of hidden trouble for Yat-sen reservoir, which is located in Zhongshan city, Guangdong province. Due to the dam axis and the original mountain being usually orthogonal, the researchers used the broken line layout and line detection of the abutment. The detection result can accurately locate leakage passages of the dam abutment, thus providing strong support for the subsequent drilling exploration and guidance for future consolidation. The above-mentioned means can provide a reliable basis for earth and rock-fill dam leakage hidden trouble detection, its evaluation and following-up consolidation.