Abstract: Based on the analysis of the composition and carbon isotopic characteristics of natural gas, it is confirmed that the natural gas of Jianglingjiang Formation has a large drying coefficient and high thermal evolution, showing an apparent feature that gas always comes from both oil-type and coaliferous source rocks, with an exception existed in Middle Sichuan region, where the accumulational gas is mainly composed by high-mature oil-type gas. The regional tectonic activities and accumulation elements of the whole basin are analyzed in this paper, the accumulation process of Jialingjiang Formation is rebuilt, and the accumulation model of natural gas of typical structural belts in the Middle, Eastern and Southern Sichuan Basin are established separately. It is found that all the Jialingjiang gas pool have experienced a long evolutionary history of ancient oil accumulation, ancient gas accumulation and current gas accumulation, and this process has a close relationship with the Indosinian movement, Yanshan movement and Himalayan movement. The law that Jialingjiang natural gas accumulation follows is as follows：fluid-drive with high
pressure, cross-layer migration of fluid, condution by fault and fracture, oil cracking to gas accumulation sealed by gypsum layers.

Key words: Sichuan Basin, Jialingjiang gas reservoir, mixed sources, accumulation model, reservoir forming rules