Abstract: Abstract：Lower Cambrian strata are well developed in Hunan. With the main sedimentary formations of black shale and carbonates in western and central Hunan and a suite of greywacke and carbonaceous slate with different thicknesses of rhythmic layers in southern area, the Lower Cambrian in the study area constitutes a second-order sequence, which can be further divided into six third-order sequences, corresponding to six orderly transgression-regression cycles. Impacted by palaeosedimentary environment, the depositional system tracts of the third-order sequences are formed by the vertical sequences of “CS + HST” and “TST (transgression system tract) + CS + HST”, with the major sequence boundaries being II type sequence boundary and the drowning-type sequence boundary. The Lower Cambrian sedimentary formation resulted from continental slope-ramp in the northwestern and central parts of Hunan; from northwest to southeast, with the gradual deepening of the sedimentary environment, the total thickness of the Lower Cambrian sedimentary formation becomes thinned. In the southern Hunan, in contrast, a suite of greywacke and carbonaceous slate of abyssal facies was deposited and becomes thickened remarkably. The sequence-stratigraphic framework records the complex palaeoenvironment evolution of passive margin in the Early Cambrian in Hunan and also reflects the restriction of the metallogenesis from palaeoenvironment evolution.