College of Geo- Exploration Science and Technology��Jilin University��Changchun 130026��China

The study on seismic anisotropy is one of the difficult problems in the field of geophysics nowadays�� As a method of ray theory�� the seismic anisotropy ray tracing is an important means to study the anisotropic seis- mic wave propagation�� The traditional ray tracing system formulated in terms of elastic parameters in the anisot- ropy is more complicated than that in the isotropic case�� Considering the difficulty��a kind of ray tracing system formulated in terms of phase velocity and group velocity is introduced�� The new method is similar to the expres- sions for isotropic media��and avoids the trouble of determining the eigenvalue vector at each time�� Besides the ray tracing numerical simulation of different models of vertical transversely isotropic (VTI) medium is carried out��in order to verify the accuracy and applicability of the method and further study the characteristics of wave field propagation in different VTI mediums�� The study is certainly valuable in reference for later processing of the anisotropic seismic data��