The ultra-deep layer with depth >6000 m is a major field of global oil and gas exploration. At present, the gas exploration in Sichuan basin has broken through the 8000 m ultra-deep layer, but the scientific questions such as whether the 8000 m ultra-deep field in the basin has the conditions for large-scale gas field accumulation, and where the favorable exploration zones are distributed have not been clearly answered. Based on the study of source rocks, favorable facies zone, reservoir, trap types, and reservoir forming assemblages, the reservoir forming conditions and favorable exploration zones in the 8000 m ultra-deep strata of Sichuan basin were evaluated in detail, and the following conclusions were obtained: (1) the ultra-deep strata of Sichuan basin is mainly developed in the Sinian-Middle Permian, and is mainly distributed in the deep western depression, northern depression and the fold belt in eastern Sichuan. Among them the western depression has the largest exploration potential; (2) the ultra-deep source rocks are obviously controlled by depressions or intra platform rifts, and mainly develop four sets of source rocks, including Doushantuo Formation (Fm), third Member of Dengying Fm, Maidiping Fm and Qiongzhusi Fm, which provide an abundant material basis for 8000 m ultra-deep gas exploration; (3) there are three basic reservoir types in the main body of Sinian-Paleozoic layer, the beach (mound) controlling porous type, karst vuggy type and dolomite porous type, which are superimposed with each other and combined with fracture altered to form large-scale multiple reservoir layers, providing favorable reservoir conditions for ultra-deep gas exploration; (4) many sets of source rocks and reservoirs communicate with each other by strike slip or thrust faults, and mainly develop two kinds of reservoir forming combinations of lower source and upper reservoir, and paraegenic and lateral reservoir assemblages forming obvious three-dimensional reservoir characteristics; (5) lithologic trap is the main trap type of ultra-deep Sinian-Permian gas reservoir in the Sichuan basin, and the structural-lithologic trap formed by anticline or nose structure superimposed lithologic body developed on the background of large slope is also an important exploration object; (6) 9 favorable exploration zones in 6 major fields, with a cumulative exploration area of more than 45000 km² are developed in the ultra-deep strata with depth more than 8000 m, and a resource volume of about 3×1012~5×1012m³ was predicted. The research of this work is of great theoretical and practical significance for the ultra-deep natural gas exploration in Sichuan basin.