Abstract: A physical flow apparatus was self-developed and the experimental method was established to investigate the gas flow in matrix-fracture system under high-temperature and high-pressure condition in deep tight gas reservoirs. The gas flow and mass transfer between matrix and natural fractures as well as artificial fractures were studied under different temperature and pressure conditions. The effects of temperature and pressure were analyzed, and the comprehensive impact of stress and flow pattern on gas flow under high temperature and high pressure was clarified. The results indicate that pressure and stress significantly affect the gas flow rate and permeability, while the effect of temperature is relatively small. The naturally fractured rocks are more significantly affected by stress sensitivity and gas slippage effect. This study provides experimental and theoretical basis for the efficient development of deep naturally fractured tight gas reservoirs.