The invention discloses a rigid-flexible coupling dynamics modeling method based on a Simulink platform. The method comprises the following steps that firstly, a system three-dimensional model is built; secondly, a system is divided into a rigid part subsystem and a flexible part subsystem, and a rigid part subsystem model is built on the Simulink platform; thirdly, modal analysis is conducted on a flexible part, and a modal analysis result is output; fourthly, according to the modal analysis result, a flexible part subsystem model is built on the Simulink platform; fifthly, the rigid part subsystem model and the flexible part subsystem model are connected, loads and constraints are applied, and building of a rigid-flexible coupling model is completed. By means of the method, efficient flexible part parameterization, automatic modeling and analysis of a flexible part rigid-flexible coupling effect can be achieved, and a support is provided for the design, analysis and optimization of a rigid-flexible coupling system.