Based on research of thin slices, cathodoluminescence, scanning electron microscope, and isotope geochemistry, we analyzed the lithologic characteristics, diagenesis and its evolution of carbonate reservoirs of the Triassic Feixianguan Formation in Jichang cliff, Dazhou-Xuanhan area. The result suggests that the evolution of depositional facies-diagenetic facies of the 2nd Member of Feixianguan Formation was related to the twice sea-level fall during the formation of the 2nd Member. The evolution of pores in the reservoirs is also related to the processes of these two regression cycles. The pore space is generated from the cementation in the sea water diagenetic environments and the dolomitization in the mixing water diagenetic environments during para\|deposional periods.