The gas-cooled microreactor is a compact mini nuclear power source designed to provide stable electrical energy for remote areas. It primarily consists of two circuits: the Primary Circuit uses helium as the working medium to cool the reactor, and the Secondary Circuit employs air as the working medium to drive turbine to generate power. These two circuits are interconnected by an intermediate heat exchanger. The reactor power regulation system is critical for the microreactor operation. This paper designs the control system for the reactor power. Based on the nonlinear model of the gas-cooled microreactor, a transfer function model for the reactor system was established using perturbation method. The dynamic characteristics of the system were investigated, and stability analysis were conducted. The nuclear power regulation system was designed using frequency domain method, and the requirements on control rod were obtained. Simulation tests were performed. The test results indicated that the designed nuclear power regulation system can effectively control nuclear power. This research holds positive implications for the development of the control for the gas-cooled microreactor.