Abstract: An electromagnetic wave propagator is proposed based on the FDTD(2,4) method. The electromagnetic wave propagation is traced by a sliding window in order to improve the computation efficiency. Due to better numerical dispersion property of the FDTD(2,4) method, the proposed propagator contains most of the time-domain information of the pulse without much truncation during the movement of the sliding window. Therefore, better accuracy can be achieved in long-distance propagation scenario. Numerical result is provided to show the advantages of the proposed propagator.