Three types of sedimentary facies including fandelta, sublacustrine fan and lacustrine facies were developed in the Member 3 of Shahejie Formation in the Area A of Huanghekou Sag, based on the studies of cores, well logs, seismic analyses and the analyses of sedimentary facies. The characteristics of sedimentary facies of the Member 3 of Shahejie Formation are typical. In the lower part of Member 3 of Shahejie Formation, the main reservoir types are fandelta and sublacustrine fan facies. Fandelta can be divided into three kinds of subfacies: fan delta plain, fan delta front and prodelta. The fan delta plain is mainly composed of  mud debris flow and channel sediments. Fan delta front includes proximal and distal bar deposits. Sublacustrine fan facies includes inner fan, middle fan and outer fan subfacies. The inner fan is mainly composed of slumping sediments and debris flow. The middle fan is dominated by debris flow and turbidity flow sediments. The outer fan is mainly composed of turbidity sediments. The distribution features of sedimentary facies of the lower part of  Member 3 of Shahejie Formation are studied.  Fan delta is located along the southern basinmargin faulted belt.  Sublacustrine fan is located in the lake area. The lacustrine facies is distributed in other areas. During the sedimentary period of the lower part of Member 3 of Shahejie Formation, the basin was a graben rifted lacustrine basin and the active basinmargin faulted belt controlled the distribution of fan delta facies.