Abstract: The Floquet-Bloch theory based on Wave Finite Element (WFE) method for dispersion curve calculation is described in this paper. In the method, the periodic condition of Floquet-Bloch theory adds on both sides of the finite scale calculation cell to approximately simulate an infinite elastic wave guide. The elastic wave dispersion curves in a plane waveguide are obtained by using the commercial Finite Element software ‘COMSOL Multiphysics’. The calculation results obtained by WFE method and spectral method are in good agreement. And, the influence of R (the length to width ratio of the calculation cell) on the correct region of the result is discussed. This method has the advantages of easy modeling and simple calculation due to avoiding the difficulties of calculating complex special functions and solving the complex transcendental equation. This method can also be extended to calculating the dispersion curves of other more complex waveguides.