Middle Triassic Leikoupo Formation is one of the important gas-bearing strata in Sichuan Basin. On the basis of comprehensive analysis of outcrops, drilled cores, laboratory, well logging and seismic data, it is shown that under control of palaeogeologic setting and eustatic fluctuations, Sichuan Basin was a water-shallow, high salty and wide barriored carbonate platform confined by palaeo-uplifts during Middle Triassic Leikoupo age. The platform was characterized basically by developing intrabasinal barriers, weak hydrodynamism, poor creature and arid climate. Leikoupo Formation beheaves an evolutional distribution of platform edge microfacies, lagoon microfacies, lagoon edge microfacies (platform interior shallow microfacies), microfacies, lagoon edge microfacies (platform interior shallow microfacies) to transitional microfacies successively from west to east in lateral and the evaporate rock, dolostone interbedded with limestone in longitudinal in the barriered platform. Some Middle Triassic Leikoupo lithofacies development and evolution maps are drawn. It is predicted that the favorable lithofacies for reservoirs develop in the peripheral regions of the barriors including the Longmen Shan Uplift in the west of the basin, and the Luzhou and Kaijiang Uplifts in the south and east of the basin.