This year marks the 80th anniversary of the victory of the Chinese People’s War of Resistance against Japanese Aggression and the World Anti-Fascist War, as well as the 80th anniversary of Taiwan’s Recovery. After the war, the geological community in Taiwan underwent a transformative period of returning from a colonial academic system and integrating into China’s geological scientific community. This paper focuses on the National Government’s reception and transformation of geological institutions in Taiwan from 1945 to 1949, exploring how they achieved integration with the geological community on the Chinese mainland and promoted the development of China’s geological discipline against the backdrop of political and social restructuring. The study sorts out the legacy issues of geological work during the Japanese occupation, analyzes the reception and expansion process through reorganizing the former “Taiwan Geological Survey” into the “Taiwan Provincial Geological Survey” and establishing the new “Taiwan Provincial Marine Research Institute”, and presents the collaborative achievements between mainland and Taiwanese geologists in mineral resource exploration, stratigraphic paleontology research, and marine geological surveys. The study shows that this process not only critically inherited the geological legacy of the Japanese occupation but also filled gaps in China’s geological science in areas such as Tertiary marine strata and island tectonics through institutional coordination, talent integration, and academic community building. It strengthened the national identity of Taiwan’s geological community, provided an important case for regional integration in modern China’s scientific development, and highlighted the interactive mechanism between political changes and geological discipline development, as well as their roles and contributions to the national geological cause.