Located at the sourthern margin of the North China Craton, the Tanzhuang—Shenqiu sag, Zhoukou depression, is filled with Lower Cretaceous sediments in a huge thinckness. Deposits in the sag are characterized by thinner grained clastic rocks with miderteran composition and texture maturations, such as mudstone, siltstone and sandstone, and especially rich in volcanic clastics. Sedimentary structures and depositional facies associations interpreted as fluvialdelta and lacustrine environments were recognized in this research. Present study insisted that sediments supply of the Tanzhuang—Shenqiu sag in Early Cretaceous are from the Dabie orogenic belt to the south. Basin's Formation was initially controlled by the southern marginal stretch fault, i.e.,Yelu fault, which became thrusting toward north at the end of Early Cretaceous. Based upon study of sandstone composition and Q—F—L diagram (Dickinson's diagram), geochemistry of major and REE elements of sediments and the geochonology of volocanic rocks, writers suggest that the Tanzhuang—Shenqiu sag formed in a regional stretch tectonic setting in the Early Cretaceous, was a original fault basin.