Based on the Markov model, a fault warning system for power grid operation is proposed. Its main objective is to improve the execution effect of alarm commands. Firstly, the power grid operation reliability evaluation model based on the Markov model is established. According to the set critical value to judge the change of power grid operation state. Develop abnormal alarm commands for power grid operation. Strange events are described in detail using natural language technology, and corresponding instructions are completed in the system. After the comparative test, the new alarm improved more remarkably than the traditional intelligent alarm mode.