The rigid-flexible coupling dynamics of a radially rotating flexible beam with impact is investigated in this paper. The transversal deformation and nonlinear coupled deformation, which means the longitudinal shortening caused by transversal deformation, is considered here. The impact force is calculated based on Hertz contact theory and nonlinear damping theory. By introducing the concept of impact potential energy, the system’s rigid-flexible coupling dynamic equations with impact is obtained by using Lagrange equation. The dynamic simulation is given to validate the method presented here, and get some dynamic response, such as impact force and flexible deformation.