Abstract: Based on multi-source data and GIS technology platform, the geological tourism resources in the Tropic of Cancer (Yunnan Section) were investigated and evaluated. The results showed: ① The geological tourism resources in the Tropic of Cancer (Yunnan Section) mainly included caves, mountain and stone landscapes, water landscapes and canyons, among which there were more resources of mountain and stone landscapes and water landscapes. ② In the study area, more geological tourism resources were found in the west, and fewer in the east, mainly distributed in Jianshui County, Mojiang Hani Autonomous County, Gejiu City, Jinggu Dai and Yi Autonomous County, Yuanjiang Hani, Yi and Dai Autonomous County, and Cangyuan Wa Autonomous County. ③ Based on the investigation and classification results, combined with the actual situation of the study area, Delphi method and analytic hierarchy process were used to evaluate and grade (1—5) the importance of the development potential of geological tourism resources in the Tropic of Cancer (Yunnan Section). The areas with Level-5 development potential are mainly distributed in the following counties and cities: Yuanjiang Hani, Yi and Dai Autonomous County, as well as the counties of Honghe, Shiping, Jianshui, Wenshan and Yanshan, and the cities of Gejiu and Mengzi. And the areas of Levels 4 and 3 development potential are in Cangyuan Wa Autonomous County, Gengma Dai and Wa Autonomous County, Jinggu Dai and Yi Autonomous County, Simao District, Mojiang Hani Autonomous County, Xichou County, Malipo County and Funing County. Meanwhile, the development potential of geological tourism resources in Shuangjiang Lahu, Wa and Dai Autonomous County is of Levels 2 and 1. In order to better develop and protect the geological tourism resources in the Tropic of Cancer (Yunnan Section), it is suggested that the following development processes should focus on the development of waterscape resources within the region, and combine the regional geographical location and folk customs, so as to make significant contribution to promoting the development of tourism industry and of tourism big health industry in Yunnan Province.