///Based on the multidisciplinary analysis of drilling core data, petrological characteristics and facies marks, this paper divides the Hetaoyuan Formation into four sedimentary systems: fan-delta deposits, braid river delta deposits, meandering river delta deposits and lacustrine deposits. The authors systematically drew lithofacies-paleogeographical maps from 3rd Member to 1st Member of the Hetaoyuan Formation. The paleogeographic distribution characteristics are as follows: fan delta is developed in the south, braid river delta occurs in the northeast, meandering river delta exists in the northwest and lacustrine sediments are developed at the center. The area of the lake expanded gradually and the braid river delta became bigger from 3rd Member to 2nd Member and began to decrease in area in 1st Member of the Hetaoyuan Formation.