Permian eyeballshaped limestone in Middle—Upper Yangtze region is a kind of carbonate with special structure , which is composed of “eyeball” and “eyelid”, and develops widely in the lower part of the Middle Permian Qixia Formation and the middle and lower part of the Middle Maokou Formation. Based on field work, combined with thin section analysis, carbon and oxygen isotope data and trace element data, the field macrocharacteristics, microcharacteristics, geochemical features and formation mechanism have been studied in detail. And differences of the macro and microcharacteristics between “eyeball” and “eyelid” are obvious. The “eyeball” is purer limestone without bedding, whose color is relatively light, and the biograins in “eyeball” mainly are algae, brachiopoda, foraminifera and fusulinids; while the most of “eyelid” is mudbearing limestones with slight wavy bedding, its color is darker, the muddy content is higher than “eyeball”, the biograins in “eyelid” dominate by shell which align orientationally, and lack algae, moreover, the diagenesis of “eyelid” is relatively intensive. Carbon and oxygen isotope research shows that “eyeball” and “eyelid” are the products in similar diagenesis environment; the trace element analysis indicates that “eyeball” is oxygen enriched deposition and “eyelid” is anoxic deposition; and trace fossil also shows that “eyelid” is anoxic deposition. According to the comprehensive analysis, the results can be conducted that “eyelid” may be the product of upwelling, and eyeballshaped limestones is formed combinatively by sedimentation and diagenesis under the influence of upwelling.