Due to the lack of horizontal comparison in carbonate facies, the sedimentary model of the Middle Devonian Guanwushan Fm. was still in dispute. Based on the field work, facies of Guanwushan Fm. in Damuya and Hejialiang were analyzed. It is suggested that the strata was dominated by rimmed carbonate platform with a short period of carbonate ramp. Guanwushan Fm. in Guixi was under the same sedimentary conditions, while not the lagoon facies. Influenced by the sea level change, three sedimentary cycles were developed. The first cycle and the third cycle were both characterized by rimmed platform deposits, while the second cycle developed carbonate ramp. Microfacies controlled the distribution of dolomite reservoir in Guanwushan Formation. Debris beach and upper slope are favorable facies, while platform edge reef and intra-beach are not favorable, especially the karst-caves formed before the migration of hydrocarbon were usually filled by dolomite and calcite.