The Carboniferous subsalt KT-II and KT-I carbonate reservoirs are the focus of exploration. The study of sedimentary facies and sedimentary model of these reservoir formations can guide the next exploration in this new area. In this paper, the sedimentary facies division and sedimentary facies evolution of KT-II and KT-I members are studied by using rock slices, logging and seismic data. The results are as follows: (1) Through the study of the characteristics of lithofacies, logging facies and seismic facies, four types of sedimentary facies are identified in the study area: restricted platform, open platform, platform margin and platform margin slope. (2) The sedimentary facies belts of KT-II and KT-I members are distributed in the NE-SW direction on the plane. Sedimentary facies change from open platform (or limited platform) to platform margin-platform margin slope towards the southeast and northwest directions, with platform margin and platform margin slope developed on the east and west sides respectively. (3) The sedimentary model of carbonate platform -platform margin slope of KT-II and KT-I members is established. Open platform is developed in KT-I member, and limited platform is developed locally, in which open platform inner shoal and limited platform inner shoal are developed respectively, open platform is developed in KT-II member, in which open platform inner shoal is mainly developed. (4) The Carboniferous in study area has experienced the sedimentary evolution process of braided river delta shallow sea shelf, isolated carbonate platform-platform margin slope, shallow sea shelf, isolated carbonate platform-platform margin slope. This article clarifies the sedimentary environment, sedimentary model and sedimentary facies distribution of the study area, and provides a basis for the next exploration deployment.