This paper firstly analyzes the principle of the interaction of the plasma and supersonic flow and then establishes a mathematic model of the plasma on the basis of the main factors affecting the interaction. The simulation of interaction of plasma and supersonic flow has been performed and tested by experiment. The results of the study show that the plasma actuation reduces the shock wave intensity and proves the energy mechanism of interaction to be proper. The numerical simulation of shock wave intensity alteration with different plasma positions, different plasma groups and different plasma temperatures has been performed. The results show that: shock wave intensity reduces with plasma position moving ahead and plasma groups increasing; there is a threshold of the temperature of plasma which could make the flow throttling. The changes of shock wave intensity become inconspicuous because 2000k has already exceeded the threshold.