Abstract: Biyang depression is characterized by developed complex fractures and multiple faulted-blocks. The key issue on looking for oil-bearing traps is to make clear the fault position and faulted-block form. Compared with post-stack migration technology, pre-stack migration technology can better and accurately reflect the structural feature. The application results indicate it can improve migration image effect and make sure the relation between fault position and faulted-blocks, which has a high degree of in line with the drilling data and has achieved obviously good geological effect. At the same time, a method centered on velocity convergence and constrained by geological message has been worked out, improving the accuracy of migration velocity.