On the basis of field outcrop profile and core observation in combination with thin sections, SEM(scanning electron microscope), CL (cathodoluminescence) and physical property analysis, the authors studied in detail the reservoir characteristics of the Permian Changxing Formation in Jiannan area. In this paper, porosity and permeability were used to synthetically evaluate Changxing Formation reservoir, and the results indicate that Type Ⅲ(low porosity-low permeability) is the major reservoir type, followed by Type Ⅳ(particularly low porosity-particularly low permeability), whereas Type Ⅱ(moderate porosity-moderate permeability) and Type Ⅰ(high porosity-high permeability) are rarely seen.