As the international situation becomes increasingly complex and the widespread adoption of intelligent and information technologies in power systems continues, power systems have emerged as prime targets for cyber-attacks, highlighting the critical importance of cybersecurity. To provide a powerful tool for studying the evolution of security risks in power network and support cyber risk prediction and command work, a wargaming-based method is proposed for modeling the evolution of power network security. A deduction framework based on the concepts of composability and minimal operation units is constructed through strategic-level wargaming simulations to achieve large-scale power network security scenario modeling and improve simulation efficiency, while effectively identifying potential risks in the network. Experimental validation demonstrates that the proposed method exhibits superior performance in large-scale power information network security wargaming, providing robust support for research on the evolution of power network security risks, optimization of cybersecurity strategies, and command operations in network security.