利用时域有限差分( FDTD) 方法，结合Matlab 编程，研究了光在突变介质界面的反射、透射与干涉.研究改变边界位 置介电系数的变化率、连续性等，对反射光强的影响; 调整薄膜厚度、电磁参数等，实现了对光干涉现象的动态建模.FDTD 方法 能够获得电磁场的时域数值解，可以直接进行动态演示; 同时，运用FDTD 方法可以通过改变介质结构，电磁参数等构筑计算 机试验，真正实现让学生自己动手，去观察，去发现隐藏在物理表象下的物理本质.

Based on the finite - difference time - domain ( FDTD) method and combined with Matlab programming，the characteristics of light reflection，transmission and interference at the interface of discontinuous medium are studied. Parameters such as the gradient and continuity of permittivity，which affect the intensity of reflected light at the interface，are discussed. Also，dynamic modeling of light interference is rebuilt on computer and systematically investigated by tuning the electromagnetic and structural parameters of the interference thin film. The FDTD method can achieve a time-domain and numerical solution of the electromagnetic field，which is very convenient for dynamic demonstration. Meanwhile，computer experiments can be realized by changing the structural and electromagnetic parameters of the cared medium，which makes it possible for students to do it themselves and to learn，to investigate the physical nature that is covered behind of those numerical physical phenomena.