Abstract: Simultaneous multi-threading (SMT) technology is one of the important micro-architecture optimization technologies to improve thread-level parallelism. SMT can realize two logical cores on one physical core and improve the overall performance of the processor. However, some timing channel security problems represented by sharing execution ports in SMT environment appeared. A port timing channel attack defending method is proposed based on dynamic resource usage strategy in SMT environment. Dynamic strategy adjustment algorithm is designed for different processing modes of data structure resources, and improved processor port binding and scheduling selection algorithm are adopted to protect the port side channel attack in SMT environment. Defending method used modular design has realized the port conflict matrix, branch filters and dynamic resource editor strategy. Respectively judgment model for port conflict, branch information filtering and SMT dynamic resource use strategy changes, the final modification strategy can be directly applied to the execution port binding and scheduling algorithm. The defending method in this paper can achieve the effect of close SMT technology and reduce the performance cost greatly. At the same time, its hardware cost is controllable. Therefore, the method proposed in this study has high application value.