Abstract: Abstract：Lower Cambrian strata are quite completely developed in southeast Guizhou, and the transitional facies characterized by intense facies change comprise an upward shallowing sedimentary succession, which constitutes a second-order sequence. This second-order sequence can be further divided into five third-order sequences. From northwest to southeast, with the change of sedimentary setting from slope to basin, Lower Cambrian strata gradually thin and eventually form a condensed succession which is difficult to divide in the third-order scale. Based on two kinds of natures of the third-order sequence, i.e., the regularity of lithofacies succession in space and the synchronism of environmental change in time, and taking the two kinds of facies-transition surface and two kinds of diachronisms in stratigraphic records as the fundamental elements in building sequence-stratigraphic framework for the Lower Cambrian strata of the study area, the authors hold that the sequence-stratigraphic framework demonstrates the special third-order sedimentary succession patterns formed after the platform drowning event caused by the rapid transgression at the early stage of Cambrian.