Abstract:The final object of seismic exploration is correef imaging for sub-surface geologic structures. It brings a lot of difficulties to 3-D seismic data processing,for 3-D seismic data acquisition can't be carried out in direction perpendicular to structural trend. The paper made application of 3-D poststack Radon projection migration to 3-D prestack processing and presented projection 3-D prestack migration algorithm. Using the principle ofRadon projection,the method projected 3-D prestack data volume onto a different radial direction, the structure in each azimuth are involved in certain or multiple radial section,forming a series of independent 2-D prestack lines,which can he processed by common 2-D prestack time migration,then,the reverse projection on time slice was applied to get final 3-D prestack time migration data volume. Real data application showed that using the method for 3-D prestack time migration resulted in obvious improvement of sig nal-to-noise ratio of the sections with weak refl}ct:on from boundary and good image for middle and deep horizons.