A conventional single dipole antenna will make the antenna power gain effect poor,and the energy of the effective excitation signal and scattering signal reflected from underground detection target(such as interface, metal target) is also weak, problems such as shallow detection depth, low target resolution, and weak signal anti-interference ability will occur. Array radar uses a multi-emission and multi-acceptance method to detect underground targets-multiple transmitting antennas simultaneously excite electromagnetic pulse signals of the same center frequency, and the electromagnetic energy is superimposed on each other. When electromagnetic waves encounter the target, obvious polarization can occur.In this paper,the complex frequency shift (CFS) perfectly matched layer (PML) is used as the absorbing boundary condition, which can effectively absorb outwardly propagating electromagnetic waves to simulate an infinite three-dimensional space.Use VTK to visualize the propagation wave field of electromagnetic waves in the three-dimensional model space, track the full waveform of electromagnetic waves in the three-dimensional model space, and analyze the polarization characteristics of electromagnetic waves under different observation methods.In order to improve the low efficiency of FDTD numerical calculation, GPU is used in the simulation to accelerate the calculation of the iterative solution of FDTD. By comparing the simulation data of the array radar and the forward data of the single-shot single-receive ground penetrating radar, it is concluded that the array radar observation method has advantages in improving the echo signal, enhancing the polarization characteristics, and improving the target resolution and accuracy.