Algebraic criteria for the periodic oscillatory synchronization of the generalized Lienard systems were derived based respectively on the stability theory of linear time-varied systems, Lyapunov direct method and Gerschgorin disc theorem. It was proven theoretically that the synchronization criteria based on Lyapunov direct method were more flexible than the criteria based on Gerschgorin disc theorem, and the criteria obtained by choosing proper Lyapunov function were more flexible than the criteria based on the stability theory of linear time-varied systems. Rayleigh-Duffing equation as a numerical example verified the theoretical results.