Security and stability control system is the second line of defense of power grid. Its correct operation plays a crucial role in the security and stability of power grid. It is introduced of the function and structure configuration of the security and stability control system in a region of the southern power grid of Hebei Province firstly. The adaptability of its control strategy is studied and analyzed in detail. Matlab/simulink software is used to model the stability control system in this area, and a variety of test scenarios are designed. Finally, based on RTplus simulation system, closed-loop simulation test is carried out to verify the control strategy and action logic of the stability control system to ensure that the stability control system meets the expected performance standards before being deployed to the actual power grid. The test results show that the stability control system can accurately select and cut load under various complex overload conditions, which can solve the problem of line overload effectively.