The gas-cooled microreactor is a highly integrated system,in which the equipment is highly coupled and mutually constrained.The dynamic simulation model of a 5 MW gas-cooled microreactor is established through theoretical derivation,and the dynamic characteristics of the system are analyzed.On this basis,the steady-state operation scheme design method of the gas-cooled microreactor is proposed.Compared with the design value,the relative error of steady-state calculation results is less than 1%.The transient calculation results of the model are consistent with the experimental results.The maximum error of flow is less than 0.53 kg/s,and the maximum error of pressure is less than 0.027 MPa.The steady-state operation scheme is as follows:at the load level of 50%FP~100%FP(full power),the helium temperature at the reactor outlet and the rotor speed remain unchanged as the load decreases;at the load level of 0%FP~50%FP,the reactor outlet helium temperature and rotor speed linearly decrease with the decrease of the load;the helium temperature at the outlet of precooler and intercooler is constant at 0%FP~100%FP load level.The proposed steady-state operation scheme ensures the safe,stable and efficient operation of the gas-cooled microreactor under a wide range of variable operating conditions.