Abstract: In this paper, we discuss the importance of investigations on microwave pulse couplings with slots for the studies of the electromagnetic compatibility, and study the coupling processes of microwave pulses into slots on a cavity wall experimentally and numerically. Some numerical simulation results and preliminary experimental results are given. The dependence of couplings on the carrier frequencies and the polarization directions of the incident waves, and the slot sizes are analysed. We observe the resonant effect and enhancement effect which occur in the processes of microwave pulse couplings with slots. We also give the condition at which resonant effect takes place.