Platform-edge reef flat facies is the most important oil and gas exploration layer of Changxing Formation around Kaijiang-Liangping trough, eastern Sichuan Basin. The lithology of the reservoir is mainly reef flat facies crystal dolomites, and it has the characteristics of broad distribution areas, great thickness and fine physical properties. Through the observation of outcrop, core and thin section, this paper studied the internal structures and development characteristics of platform-edge reefs in the study area. The result shows that the platform-edge reefs have very different sedimentary characteristics in different places near the trough, and could be divided into patch reefs and mound reefs according to the development scales. Because of the different palaeogeomorphology and sea-level change，the patch reefs and mound reefs possess different evolution stages and reservoir characteristics. The patch reefs developed with the characteristics of shorter formation time, thinner reservoir thickness and poor properties, while the mound reefs mainly developed with the characteristics of larger formation time, thicker reservoir thickness and fine properties. Platform-edge reefs reservoir belongs to low porosity and low permeability reservoir. As a kind of the platform edge reefs, the mound reefs reservoir is better than that of patch reefs, and the patch reefs reservoir developed in the second period of Changxing Formation is better than patch reefs reservoir developed in the first period of Changxing Formation.