The reservoir in Mahu area is affected by the reservoir characteristics, the formation pressure drops greatly, the production decreases rapidly, the forecast recovery ratio is low, and the stable production is difficult. In order to improve the production effect of Mahu tight sandstone reservoir, the reservoir and fluid conditions of a well area in Mahu are simulated in laboratory, taking Mahu tight sandstone as the research object, multi-round stimulation experiments of hydrocarbon injection and CO2 injection were carried out. The experimental results show that the maximum expansion coefficient of CO2 increases to 1.58, the expansion coefficient increases by 58% and the maximum expansion coefficient of hydrocarbon gas increases to 1.50 with the injection of gas, the swelling coefficient increased by 50%, the ratio of dissolved gas to oil increased gradually, and the ratio of dissolved gas to oil injected with CO2 was always higher than that injected with hydrocarbon. The viscosity and density of crude oil decreased obviously, and the viscosity of formation crude oil decreased from 1.9 mpa.s is down to 1.38 mpa.s (hydrocarbon injection) and 1.02 mpa.s (injected CO2), the viscosity reduction range is 27.37% (injected hydrocarbon gas) and 46.31% (injected CO2) respectively. The efficiency of hydrocarbon injection and CO2 injection is 37.91% and 40.56%, respectively, and the crude oil in the large and medium pores is mainly used, and the crude oil in the large pores is almost completely replaced, CO2 Injection stimulation can further improve the oil in small and medium pores, compared with gas injection, CO2 Injection stimulation is more conducive to the development of Mahu tight fine sandstone reservoir. This study provides a technical reference for enhancing oil recovery in the later stage of Mahu Tight Reservoir.