PID (Proportion Integration Differentiation) controller has the problem of low applicability to the core power control process, which can be well solved by using genetic algorithm(Genetic Algorithm,GA)to adjust the PID controller parameters. Based on the PID controller of genetic algorithm and the state space model of the core, the power control system of the core of the lead cooled fast reactor is established in this paper. The response of the system under the core reactivity and the core inlet temperature disturbance is simulated and compared with the control result of the PID controller. The results show that when there is disturbance outside, the core can reach a stable state with little deviation from the initial state, and the control effect of genetic algorithm PID controller is more significant than that of PID controller.