Abstract：During most time of Middle Devonian-Late Permian period, the Nanpanjiang depression was in an environment of isolated carbonate platform surrounded by a deep sea trough and formed by extensional faulting during the evolution of the Nanpanjiang Ocean. The platform was a land platform during the period from late Early Carboniferous to Late Carboniferous. The field exploration of Late Paleozoic strata in Longlin area revealed six kinds of sedimentary facies types in the isolated platform-trough facies region, i.e., carbonate tidal flat, restricted platform, platform margin beach, platform margin reef, shelf between platforms, and basin between platforms，and established a sedimentary model for the unique isolated platform. The current study shows that its evolution experienced four stages of development, namely, marginal carbonate platform（D1-D2）, isolated carbonate platform（D3-C11）, land platform（C21-C2） and isolated-drowned carbonate platform (P), implying that during the Late Paleozoic period, the Nanpanjiang basin evolved from rifting to a small oceanic basin with intense expansion and subsidence, while the southern margin of the Yangtze Platform experienced extension and breaking splitting.