采用时域有限差分方法(FDTD)对高功率微波(HPM)近地面传输进行了仿真，其中提出的一种完全匹配层-广义完全匹配层混合吸收边界，较好地抑制了常规FDTD方法在计算低掠射角入射时产生的边缘绕射现象。将理想水平地面数值计算结果与解析法结果对比验证计算模型的正确性，通过数值计算结果分析高功率微波粗糙地面的散射特性。理论分析和仿真结果表明：粗糙地面对散射系数变化影响较明显，从宏观角度上看，散射系数曲线同理想水平地面散射系数曲线相似，即随掠射角的增大散射系数先减小后增大；从微观角度上看，由于粗糙地面的作用，其散射系数曲线并不存在布鲁斯特角，且在某一区域并非单调增加或减小。

High power microwave (HPM) subaerial propagation is simulated with finite difference time domain (FDTD) method. In the simulation, a mixed absorbing boundary is presented by combining perfectly matched layer (PML) with generalized perfectly matched layer (GPML).The correctness of the model is verified by contrasting the numerical value with the analytic value at level ground, and the scattering properties of HPM is analyzed by the numerical values at rough ground.Theoretical analyses and simulation results show that, diffraction phenomena arising from the edge can be restrained by using this method. The scattering coefficient curve of rough surface is similar to that at level ground in overall trend, however, it has no Brewster angle.