A meshfree method based on polynominal point interpolation method (PIM) is proposed for dynamic analysis of a rotating cantilever beam; PIM is used to describe the deformation of the flexible beam. Its longitudinal and transverse deformations are both taken into consideration, and the coupling term of the deformation which is caused by the transverse deformation is included in the longitudinal deformation of the beam. The rigid-flexible coupling dynamic equations of the system are derived via employing Lagrange's equations of the second kind. Compared with the finite element method (FEM), only individual nodal data are required in the current method so that its preprocessor is easier, and the shape functions constructed have high-order continuities due to more nodes to be interpolated. Simulation results of the meshfree method are compared with those obtained by using FEM and assumption of modes method. It is demonstrated that the meshfree method can be extended to the field of multibody system dynamics.