Abstract: The aim of the conventional processing of 3D seismic data is to explore oil and gas in the deeper part.However,shallow layers become the target when we use 3D seismic data to evaluate the geologic conditions and geohazard in shallow part.Processing tests were carried out in order to find out suitable parameters for improving the resolution of shallow layers.Reprocessing of 3D seismic data covering an area of 1 248 km² in the Qiongdongnan Basin was conducted using different offsets.Three seismic data volume was obtained.The seismic data volume of 250~1 650 offset was chosen to assess the geologic conditions and geohazard in shallow depth after analysis of the resolution and signal-to-noise ratio of the three seismic date volume.