The stability control system is a facility critical for the power grid operating safely and stably in the event of severe faults. The failure of its devices or communication channels can impact on the operation of the power grid seriously. Based on analysis of the business functions and control architecture of the stability control system, a stable control system modeling and risk quantification evaluation method based on control strategies has been proposed. Firstly, a logical correlation model for the stability control system and communication network is constructed. Then, a quantitative evaluation method of stability control system risk based on strategic control quantity is proposed. Finally, based on a typical power grid scenario, the rationality and usability of the method were analyzed and verified.