The invention provides a composite material elastic parameter identification method based on a substructure, establishes a composite material substructure finite element model, and carries out dynamicpolycondensation on the composite material substructure model according to the substructure theory; after the substructure eigenmatrix is assembled on the residual structure, the modal information ofthe whole composite model is obtained. The relative sensitivity of the modal frequency to the elastic parameters of the residual structure is calculated by extracting the modal data of the whole model. The objective function is minimized by iterative optimization algorithm with the two norm of modal frequency residuals of experiment and finite element simulation as the objective function. By considering the composite material modeling of the sub-structure, the model to be identified is defined as a residual structure. By means of modal frequency sensitivity analysis and modal mode matching, the parameters to be identified of composite materials are identified by optimization iterative algorithm, which saves computational resources and improves computational efficiency. It has very important engineering significance.