Abstract: Based on field investigation of exposed sequence stratigraphy and referred Triassic sea-level changes in South Chins, sequences of two 3rd order and seven 4th order of Lower and Middle Triassic are established in this paper. In addition, the Triassic sequence stratigraphy framework of Guizhou is constructed，which is the first detailed sequence division of Triassic in Guishou and is important to further pa1eogeography and facies studies. This paper also studies the geochemistry and distribution of trace elements in the Triassic strata. The relationship between trace elements and sequence stratigraphy is discussed. It is suggested that the enrichment of Pb，Ba，Mn，Si，Ga and Ni was caused by hydrotherma1, activities accompanied with intercontinental tensile subsidence in the passive continental margin.