Based on the measure d profiles , the sedimentary characteristics of Upper Permian Changxing and Dalong Formation are studied. The result shows that since fromthe early depositional stage of Late Permian Changxing Formation, Guangyuan-Liangping area is a gulf which formed by the rifted synsedimentary fault in Upper Yangtze Platform; in Changxing Formation in Yudongliang and Pingshang area in Jiangyou, there developed tidal and open platform, with bioclastic shoal, and there also developed immature sponge reefs in Pingshang area; in Changjianggou area in Jiange, there developed deep water sedimentation in Dalong Formation which is at the same stage with Changxing Formation, and it is rich in calthrop and radiolarians. The main reservoir spaces are intergranular dissolved pore, intergranular pore,fractured cavern, structural fracture and dissolved fracture. In a word, reefs at the margin of Guangyuan-Wangcang gulf are located between Erlangmiao in Jiangyou and Xiasi in Guangyuan, where Changxing Formation is deep buried, and they are the favorable area for exploration of underground reef-beach reservoir.