Piedmont high and complex structure imaging of the western foreland basin has become bottleneck of seismic exploration. The conventional seismic imaging method couldn't get correct imaging because of the limit of its algorithm and adaptability. We analyses the advantages of pre-stack depth migration of Kirchhoff integral method, and introduce its main techniques. Aiming at such problems as low signal to noise ratio of the normal seismic data, and difficult to migrate high and steep structure and so on, we achieve a method that combines with pre-stack time migration, post-stack depth migration and prestack depth migration, and uses the best fitting method to obtain velocity model exactly, to do pre-stack depth migration, and to achieve actual structure finally. Finally the comparison analysis aiming at 2D survey lines of piedmont zone confirms the effectiveness of the pre-stack depth migration method for piedmont complex structure imaging.