Potassium channels play an important role in repolarizing the nerve cell action potentials. There are many types of potassium channel proteins, and potassium channels allow potassium ions to specifically pass through the cell membrane, thereby maintaining the resting potential of nerve cells. In this paper, molecular dynamics simulation method is used to simulate the effects of 53.7 THz terahertz wave with different amplitudes on the secondary structure of KcsA potassium channel protein and the potassium ions rate. It is found in this study that under the action of the 53.7 THz terahertz wave, the number of alpha helices in KcsA potassium channel protein decreases, and the number of beta sheets and the number of coils increase. In addition, the 53.7 THz terahertz wave can accelerate potassium ions through the KcsA potassium channel. In this article, the effects of terahertz waves on potassium channel proteins are analyzed through the secondary structure of proteins, and a new perspective for the interaction between terahertz waves and biological functional molecules is presented as well.