Abstract: The accumulation mechanism of natural gas is still an unsolved problem in the Lower Triassic Jialingjiang Formation of Moxi-Longnüsi area in the middle of Sichuan Basin.The former researcheres considerates that the natural gas of Jialingjiang comes from the underlay Permian source rocks,and this paper mainly rebuilds the maturity history and thermal history of the Permian source rocks in the study area,by combining technologies of apatite fission tack and basin-modelling.Based on the researches mentioned aboved,the paper analyzed the fluid pressure evolution and the formation process of migration pathway,and the accumulation process of natural gas.The paper establish the accumulation model of natural gas of Moxi-Longnüsi structural area,and summarizes the following hydrocarbon accumulation: fluid-drive with high pressure,conduction by fracture,vertical migration of fluid,oil cracking to gas accumulation sealed by gypsum layers.