Abstract: The Shanjiang fold system ia a part of the Indosinian geosynclinal fold region of the Tethys-Himalaya Tectonic Domain in southwestern China, which was determined to be generated by the lndosinian folding movement firstly by Ren Jishun et al. （1964. 1966）. who pointed out that the main folding phase is represented by unconformities between the Carnian and Norian of the Late Triassic. Authors’s recent surveys show that the main folding phase is mainly marked by unconformities between the terminal Middle Triassic and the Late Triassic Carnian. The most pronounced localities of the unconformities are in the Jinshan River and Lancang River eugeosynclinal zones. Hore the Lower-Middle Triassic is composed of a considerable thickness of arenaceous-pelitic and volcanic- sedimentary flysches, which are characterized by repeated rhythms, complex structures and generally undergoing metamorphism. The volcanic rocks exhibit the features of oceanic island-arc rocks, which, together with syntectonic igneous rocks, constitute an Indosinian tectono-magmatic belt that extends discontinuously for 1000 km. However, Upper Triassic Carnian and post-Carnian strata are all represented by sandstones, shales and carbonate rocks, showing the nature of a stable platform cover. Angular unconformities beween the Middle and Upper Triassic are found in some places.