The authors employ the high-density resistivity method to image the subsurface structure of a moun-tain in Erdaojiang District, Tonghua City, Jilin Province, China, to evaluate the potential risk of slope failure on surrounding residential areas and infrastructure, and identify a shallow fault that extends across the center of the mountain and is perpendicular to the mountain slope and accurately locate the spatial position and depth of another fault on the southern side of the mountain. The results provide an important basis for evaluating moun-tain slope stability. This study also demonstrates that the high-density resistivity method is effective for detecting mountain faults.