Abstract: In deep water drilling engineering,accurate formation pressure profile is the key analysis data necessary to determine the density window of safe drilling fluid.Combined with the geological conditions of the L-1 well area in the south China sea,an optimal pressure prediction model was developed based on a large number of field data comparisons,and the formation parameter data obtained from the well logging were used to comprehensively analyze the L-1 located in the central structure of the Yinggehai basin.The calculation and analysis of formation pore pressure,fracture pressure and wall collapse pressure were performed in the well area,and the formation pressure profile of the well area was obtained to predict the safe drilling fluid density window.Compared with the actual measured points near the well,the prediction error of the formation pressure is less than 10%,which provides a basic theoretical support for engineering development.