By applying the dyadic Green function, the dispersion relation of two-dimensional photonic crystal can be ex pressed as the cylindrical wave expansions of eigenmodes. With the aid of Greens theorem, the plane-wavecoefficients of eigenmodes are reconstructed and employed to formulate the scattering matrix of finite-height twodimensional photonic crystal. These operations make the convergence rate very rapid, and reduce the dimension of the scattering matrix. As a demonstration, we present the transmission and electromagnetic field distributions for an InGaAsIn photonic crystal, and investigate their convergence.