Abstract: Carboniferous strata are well developed in Fengshou area of Aohan Qi, Inner Mongolia. The Upper Carboniferous Jiujuzi Formation, composed of a set of terrigenous clastic rocks, is specific in the region. Based on the rock assemblage, fabrics and vertical variation regular pattern, one sequence of third-order is recognized, including two sequences of forthorder and five sequences of fifth-order(high frequency cyclic sequence).