The Low Middle Triassic in the Sichuan basin contains several sets of the salt layers. The characteristics of the salt layers are thick, wide distribution and well marked depositional cycles. Nowadays, the research of the sedimentary and the lithofacies palepgeography in Sichuan basin usually service for the oil and gas exploration. There is few research of the micro phase related to the evaporation and salt forming. On the basis of the previous studies and the information about looking for the salt, potash, oil, and gas, this paper divides the Sichuan basin into 18 secondary salt basins and 5 salt forming zones. By taking the carbonate platform as the emphasis, according to the sedimentary structure, biological characteristics and lithofacies associations, 18 types rocks in the low middle Triassic have been classified. They constitute 3 different sedimentary facies (open platform, restricted platform and evaporate platform), 6 kinds of subfacies and 13 kinds of sedimentary microfacies. According to the sedimentary distribution of the salt layer, 4 pieces of lithofacies paleogeographic map have been drawn in this paper, including 4 main period of the salt forming, T1j4-2, T1j5-2-T2l1-1, T2l3-2, T2l4-2. The every sedimentary facies has the salt lake as the core and distribute as belt, with the form of the bull’s eye type zoning. In summary, the salt forming model of Sichuan basin in Early Middle Triassic could be concluded as “the small playa lake with a bull's eye type zoning in supratidal environment”.