Abstract: Since Zhenyuan gas field, one of the first gas fields in the world, was drilled successfully in Sinian Dengying Formation of Weiji well in Weiyuan structure in 1964, no significant breakthrough has been made in Sichuan Basin after nearly 50 years? exploration. Five types of sedimentary facies developed in early Dengying Formation of Late Sinian of the basin, i.e. the carbonate tidal flat facies of platform, the carbonate tidal-flat facies on top of the platform lagoon, the carbonate shallow ramp facies of platform, the carbonate shallow ramp facies held by lagoon facies of platform, and the carbonate deep-shallow ramp facies of platform. Through comprehensive study on available data, four successive paleohighs including Yaan-Longnvsi paleohigh, Luzhou paleohigh, Tianjingshan paleohigh, and Kaijiang paleohigh had been formed as early as the Caledonian end of the basin, and they are favorable for oil and gas accumulation. Also the drill depth could be fulfilled by use of current drilling technologies. But in Kaijiang paleohigh, with less drilled wells, whether there are uplifts in Dengying Formation needs to be proved through seismic work

Key words: Sichuan Basin, Sinian, Dengying Formation, natural gas, exploration