Stokes vector has been used to deal with the polarization properties of anisotropio cavities, including both active and passive cavities. The equation of motion of Stokes polarization vector is derived in an anisotropio cavity in which the gain coeffecient of active medium, the dielectric coeffecient and the loss of cavity all are anisotropic. Analytic expressions for the eigen-states of polarization, eigen-frequencies and frequency splitting axe given.