Abstract: Prestack depth migration is by now one of the most advanced and accurate seismic imaging technology, which mainly includes Kirchhoff integral method and wave-field continuation method (wave equation method). First we describe the principle of Kirchhoff prestack depth migration. Then the detailed procedure of application is discussed:initial velocity model creation, output of common imaging gather with large grid, migration velocity analysis and velocity model updating, and final prestack depth migration. A case study on 2-D and 3-D seismic data is played in the East China Sea and the imaging results are com pared with that of prestack time migration.Finally we discuss some issues for the application of prestack depth migration.