Abstract: The access of renewable energy such as wind power brings more challenges to the safe operation of the power system. In this paper, the basic construction method of dynamic security region (DSR) boundary is introduced. This paper analyzes the differences in the dynamic security regions by changing access nodes. It is concluded that the distance between the access node and the balancer is negatively related to the transient stability of the power system. Test results on the New England 3-genrator 9-bus system are presented and prove the correctness of the conclusion.