Numerical dispersion resulting from using the second-order central-difference operation to approximate the differential operation is the main error source of the FDTD method. The effect of numerical dispersion can be minimized if the spatial grid size is small than£f/10. It is difficultly to analyze the modeling of electrically large structures since a huge amount of computer memory will be needed if using a very fine grid to discretize the structure. Using higher-order FDTD is the effective alternative to reduce the effect of numerical dispersion. In this paper will discuss the handling of the discontinuous PEC boundary condition in four-order FDTD and its applications to antenna pattern analysis. Using the fourth-order FDTD can enlarge the spatial grid size and reduce the requirement of computer¡¦s memory. The far field range of small size antenna operating at higher frequency is shorter enough to directly derive the far field pattern by enlarging the spatial size of fourth-order FDTD. It will compare the far field pattern derived by four-order FDTD with near-to-far field transformation and analyze their characteristic individually.