Abstract: Regarding the multiple solutions of velocity inversion of pre-stack depth migration（PSDM）and the mismatch between horizon calibration and migration results, and taking the seismic data of a district with complex structures in Iraq as a case, the paper detailedly introduces the VTI media (Transversely Isotropy with vertical axis of symmetry) Kirchhoff PSDM technology and its application and notices. The paper proposes a combined method which uses interval velocity inversion with interval-stripping velocity correction method and logging curve trend constrain method to solve the multiplicity problem; obtains the initial interval velocity through constrained velocity inversion(CVI) in a root-mean-square velocity field of pre-stack time migration to ensure the accuracy of the initial interval velocity field and effectively decrease the iteration numbers of interval velocity inversion with interval-stripping velocity correction method; and solves the mismatch between the migration results and horizon calibration by using VTI media migration. The actual application results show that the above mentioned Kirchhoff pre-stack depth migration process and its notices can effectively improve the work efficiency of pre-stack depth migration and obtain more reliable velocity model in depth domain, and can increase the accuracy of velocity inversion to obtain horizons corresponding to drilling stratification