Abstract: Carbonate platform-basin facies developed during the early Triassic Feixianguan Formation in the northwestern margin of the Upper Yangtze. Studies of rock characteristics under microscope, such as its structure and formation, provide intuitive evidence for research on sedimentary environment and biological resuscitation in the early Triassic after the Late Permian mass extinction. In this study, we selected four field sections of the Lower Triassic Feixianguan Formation from open platform, platform margin, and pre-platform slope-basin multiphase belt in northwestern Upper Yangtze, from which common slices were systematically sampled and made. Photomicrographs of the slices were taken to systematically display the type, mineral composition, structure, formation, paleontology, diagenesis, etc. of the rock sections. This dataset consists of two parts, including a total of 1082 polarizing micrographs of 330 rock samples from geological four sections, and a sheet information table. The dataset can provide basic material for research on the early Triassic paleoclimate, paleoenvironment, and paleontological resuscitation, or research on sedimentary differentiation of different facies in this period. It also provides data support for oil and gas survey on this particular strata.