Abstract: In order to quantitatively study the coupling terminal response electromagnetic wave and microstrip line, a coupling analysis method was proposed based on the BLT equation. It greatly improve the computational efficiency and occupies less memory, compared with traditional methods. The microstrip line on the printed circuit board (PCB) was equivalent to a lossy transmission line, and the plane wave vector was analyzed and the effective excitation source was solved, The influence of different incident waves and incidence angles on the microstrip line terminal was investigated using the BLT equation. The time-domain and frequency-domain analyses on the incident wave and terminal response were performed. The results show that, when the frequency of the incident wave has a certain relationship with the microstrip line, the peak coupling voltage reaches a maximum of 2.4 mV; the terminal peak voltage, when electric field is parallel to the microstrip line, is twice that for electric field perpendicular to the PCB; the peak coupling voltage of the microstrip line caused by rectangular pulses is larger than those for Gaussian pulses and triangular pulse with the same amplitude and pulse width; the terminal coupling voltage could reach millivolt level by adjusting the pulse width of different pulses.