A whole dynamical model is often built to analyze the dynamic characteristics of exactly one part, because the rotor system has a complex structure and a strong coupling effect between its parts. For example, in a plate or blade, the degrees of freedom of the complete machine finite element model are enormous, and the computational efficiency is low. A constrained parameters identification method for the local restriction is proposed to increase the computational efficiency and make it easier to analyze the part's vibration. A constrained parameters identification method for local restriction is present, considering the subsystem coupling effects in a complex system. The rotor system is resolved and decomposed into the axis and plate and the subsystem and main system are established. Considering the subsystem coupling effects in the complex system, the restrain stiffness and dampness of the boundary unit can be identified by deducing the dynamical equation. The nodes response of the finite element model can be computed and compared with the corresponding nodes of the whole model. The results show that the equations are correct. This method can be used in the vibration analysis modeling of the rotating structure to save computing resources.