Abstract: Conglomerate reservoirs with abundant oil and gas resources have been found in Daxing fault zone successively such as Xing 8 and Xing 9 etc. Most of these reservoirs are mid-fan braided channel of nearshore subaqueous fans. Therefore, it is very important to study the sedimentary characteristics of the nearshore subaqueous fans. Based on the previous research results and the latest core，seismic, well logging and other data obtained in the sag, the sedimentary microfacies are identified and classified in this paper. The vertical and horizontal distributions of the nearshore subaqueous fans are summarized and the depositional models of them are established for debris flow and mud flow, respectively. The debris flow nearshore subaqueous fan is developed in Jiuzhou area with an abrupt contact between the thick conglomerate and mudstone in the fan body. The sediments are mainly composed of particle-supporting conglomerates with little matrix. Whereas, the mud flow nearshore subaqueous fan is found in Gu’an area. Few channel exists in the fan and the sediments are mainly matrix-supporting conglomerates with the matrix dominated by mud. The debris flow nearshore subaqueous fan can be classified into six sedimentary microfacies such as main channel of root fan, interchannel of root fan, braided channel in midfan, braided interchannel in midfan, sheet sand in endfan and mud in endfan, among which the braided channel in midfan is the main body of the midfan and even the debris flow nearshore subaqueous fans. The endfan is relatively undeveloped. The nearshore subaqueous fans are in near NE trending distribution along Daxing fault zone with the lower third member of Shahejie formation being the most developed