The stability and correctness of the parameters in the dynamic model of PWR（ Pressurized Water Reactor）nuclear power unit are of great significance to ensure the transient stability of the system

so it is necessary to design a suitable parameter evaluation method. The dynamic model of PWR nuclear power unit is divided into multiple submodule models according to its internal physical boundaries. According to the derivation for the differential equation mathematical model of each sub-module

the influence of the parameter variation on the steady-state output variables of each sub-module are estimated qualitatively based on the transfer function of variable deviation. In order to improve the efficiency and accuracy of parameter obtainment

a reasonable parameter acquisition scheme is chosen based on the determination of the sensitivity index value and whether the final value of the parameter sensitivity is zero. Particle swarm optimization algorithm based on the perturbation of the group optimal value is applied to obtain the model parameters

and the results of the example verify the effectiveness of the proposed parameter evaluation method.