The application of high-density resistivity method in the tunneling engineering geophysical is discussed in the paper. Based on the field geological surveying, in Xizhouling Tunnel section in the project of Xizhouling Tunnel and Xikou Tunnel in the expressway of Yunhe to Jingning, topography and geomorphology is low mountains landform, the geological condition is complicated. The tunnel passes through the town of Anxi Family at the depth of 150 meters and a NE fault crosses according to surface evidence. In order to find out the NE fault is existed or not and survey its scale and influence depth, geological investigation method can cause the high equipment cost and limited investigation depth by the influence of underground cable and terrain, and the investigation precision is difficult to meet the requirement. Based on the basic principal of high-density resistivity method, the paper proposes the superior features of high-density resistivity method compared with conventional resistivity method. this method can not only collect field data largely, but also can process and interpret achievement data visually and vividly. Especially high-density resistivity method is better than other resistivity method on the determination of fault properties. By the comparison and selection of projects, high-density resistivity method is applied in exploration and research. The successful application of high-density resistivity method in engineering exploration shows that the high-density resistivity method can complete the complex geological condition exploration of low hilly areas, reduces the drilling workload and save economic investment of exploration, designing, construction and so on.