During the Mid-Permian Maokouan stage, the Middle-Upper Yangtze region was covered by carbonate rocks. One kind of special structure of these carbonate rocks is named eyeball-shaped limestone, composed of the "eyeball" and "eyelids" components. It is widely distributed in the mid-lower part of Maokou Formation in Sichuan Basin. "Eyeball" is lighter in color, enriched in bioclastic, while "eyelids" are darker in color, dominated by marl. Through field observations and laboratory studies on a typical eyeball-shaped limestone from Maokou Formation at Dapuzi section, Nanchuan, Chongqing. We proposed that a shift in environment deposited the "eyeball" and "eyelids" might have been resulted in the difference in the precursor sediments. During the early diagenesis, carbonate dominated sediments were cemented and prevented from destroyed by mechanical and chemical compaction. In contrast, "eyelids" layers were compacted due to insufficient cementation. Thus, the origin of the eyeball-shaped limestone in this study was attributed to the combined effects of sedimentary and diagenetic processes, and formed shallow shelf sedimentary environments.