In this paper, Finite-Difference-Time-Domain method is used to calculate and simulate the propagation of EM wave in anisotropic medium. As a demonstration, numerical results for the case of negative uniaxial crystal are presented. From these results, the birefringence and polarization splitting effects are clearly shown and well agree with the analyticgraphic ones. It has been shown that the method can be used in analyzing the general propagation problem of EM wave in anisotropic medium.