An improved finite difference method in solving vector wave equations based on H fields for full-vectorial analysis of optical waveguides is described.A six-point finite difference scheme of high accuracy is constructed to approximate cross-coupling terms.It takes into account the discontinuities in derivatives of magnetic component at horizontal and vertical interfaces.Moreover,the scheme is independent of structure of waveguide due to explicit expressions.The guided-mode patterns and normalized propagation constants of a step-index fiber,a rectangular waveguide and a rib waveguide are presented.The hybrid nature of full-vectorial guided-modes is demonstrated.The results agree well with analytical solutions and the benchmark results of modal transverse resonance method.It demonstrates accuracy and convergence of the method.