Abstract: Based on the characteristics of hydrocarbon source rock development and the types of oil and gas reservoirs, the Upper Triassic-Jurassic oil and gas system in Sichuan Basin is further divided into two sub-systems - Upper Triassic and Jurassic. Taking the fundamental elements of the oil and gas systems as the basis for the study, this article is focused on the migration and accumulation conditions, main controlling factors and the abundance law of Upper Triassic oil and gas system and Jurassic oil and gas system. The main controlling factors for migration and accumulation of Upper Triassic oil and gas system are the strong gas infill sources and the palaeohigh and faulted fractures of Yanshanian Period. Late Jurassic and Early Cretaceous are the main stages for formation the gas reservoirs. Jurassic oil and gas system has the different migration and accumulation laws and main controlling factors in the different zones and belts. The oil and gas reservoirs in Central Sichuan region are formed mainly under the control of fourmain factors - oil source zone, palaeohigh, fault or fracture, and extension of effective reservoir body, leading to existence of fracture-ligthologic oil reservoirs. The oil and gas reservoirs in Bazhong-Pingchang region are controlled mainly by the hydrocarbon generation center and fracture, leading to existence of lithologic-fracture oil reservoirs. The main controlled factors for the reservoirs in Dabashan frontal area are fracture, effective reservoir sandbody and storage condition, leading to existence of fracture-lithologic oil and gas reservoirs