A study of environmental geology and hot spring utilization was conducted at the Dongpu Hot Springs and the surrounding area in Nantou County, covering a total area of 4 km2. The study found that exposed terranes beginning with the Shibachongsi terrane from the Eocene epoch, which had a green igneous rock mass inside of it. The next layer was the Heshe terrane from the Miocene epoch, the terrace accumulative terrane from the Quaternary epoch, and the modern alluvium. The two main exposed faults were Fault A and Fault B. The potential environmental geological mechanism included: faults, new and old rock avalanches, colluvial deposits, gully erosion, and landfill zones. The hot springs come to the surface at three points, two of which were in the Basiang River valley, and one of which was on the middle of a hillside. However, all three lie on the intersection of the formation and Fault A, which indicates that hot spring activities have a close relationship with Fault A. A distribution map of ground heat signs, a ground heat geological map, and an environmental geological map were made during the study. All maps were made on a scale of 1:5000.