Abstract: The Sanjiang (Nujiang River, Lancangjiang River and Jinshajiang River) orogenic belt in Southwest China, which connects the Qinghai-Tibet Plateau in the north and Southeast Asia in the south together, is the key place for the study of Tethys.Based on the review of the important progress made in the past ten years in the study of Tethys in the Sanjiang orogenic belt in the early Paleozoic Tethys, high-pressure metamorphic eclogite belt and back arc basin suture, four key geological problems to be solved were pointed out, including whether Ganzi-Litang Tethys ocean and Yidun island arc once existed or not, the tectonic environment of ultrabasic rocks in the Luxi-Ruili belt and geological significance of the Carboniferous-Permian assemblage of basalt, and carbonate in Changning-Menglian belt and space-time configuration of Proto-Tethys were summarized.On this basis, the following three key directions of Tethys research in the future are proposed, the further perfection of the structural framework in Sanjiang orogenic belt, exploration of the transformation process between the Proto-Tethys and the Paleo-Tethys, the multidisciplinary comprehensive research and simulation of paleontology, paleogematology, geology and geochemistry to create qualitative to semi-quantitative and quantitative research on Tethys dynamics.