This study determined the lithological association and identified sedimentary facies of Triassic in the Hongqiba region through analyzing core samples, wireline log patterns, and seismic facies. The spatial variation of the sedimentary system in the Triassic was then determined based on source supply and hydrodynamic conditions. Results show that the Triassic in the Hongqiba region was dominated by coarse deposits derived from fan delta deposition system, including fan delta plain, fan delta front, and pre-fan delta. Primary microfacies are distributary channel, underwater distributary channel, inter-distributary bay, and distal bar. Climate changing from drought to humidity during the Triassic resulted in widespread lake transgression.