Abstract: Analysis of sediment source is an important part of reconstruction of lothofacies palaeogeographic conditions in a sedimentary basin. Source analysis is mainly to determine source direction, location of erosion/mother rock areas, distance of transportation and character of mother rocks through studying terrigenous detrital components and their architectural and structural characteristics. The sediment source of the upper 2nd member of Shahejie Fm in Wang3 block of Xianhe oilfield is studied through comprehensive analysis of logging, core and seismic data and by using the principles and methodologies of mathematical geology. The lothofacies palaeogeographic framework in the study area is finally identified and the distribution patterns of sandstone layers and sandbodies are determined. Studies of the source direction in Wang3 block with different methods achieve the same conclusion, i. e. the sediments were mainly sourced from the south in the late stage of deposition of the 2nd member of Shahejie Fm.