The work aims to carry out dynamic modeling and simulation study of a 3-DOF parallel packaging mechanism, so as to improve its dynamic performance. Firstly, the three-dimensional model of the mechanism was established and the inverse solution of mechanism position was calculated. Then, Kane's method was used to list the dynamic equations. Based on the modal analysis of the branch chain, the rigid-flexible coupling dynamic analysis of the mechanism was carried out by transforming the connecting rods from rigid bodies to flexible bodies, relying on the multi-body dynamic simulation software ADAMS and the finite element software Ansys. The driving force of the drive rods in generalized coordinates were obtained by dynamic modeling. From the modal analysis, the natural frequencies of the first order to the sixth order were respectively 88.656, 108.95, 119.96, 125.33, 131.07 and 138.77 Hz and the vibration mode of the mechanism in each order was obtained. The motion displacement, velocity, acceleration of moving platform centroid and change curves of joint driving force and moment of the mechanism were obtained. The weak link of the rigidity in the parallel packaging mechanism is located at the two ends of the spherical hinge connection, the position with large relative displacement of vibration in the modal shape of each order is located at the moving platform and the slide block in the middle of branch chain, and the connecting rods have certain influence on the motion performance and joint driving force of the moving platform. The analysis results provide a theoretical basis for further optimization of the parallel mechanism.