The elastic deformation of the flexible link in the spatial closed-chain robot under high-speed operation has an important impact on the vibration effect of the system. In order to accurately analyze the influence of the flexible link on the vibration characteristics of the spatial flexible closed-chain parallel robot, the finite element method was used to discretize the flexible link, and then the component displacement vector was described by the floating frame reference method. Finally, the spatial rigid-flexible coupling closed-chain robot was established based on the Lagrange equations dynamic model and vibration equation, and the system natural frequency and vibration mode function were analyzed. Based on the same parameter conditions, the ADAMS/Vibration module was used to establish the vibration simulation model of the spatial rigid-flexible coupling closed-chain robot, and the self-excited vibration analysis was carried out to study the change of the system natural frequency and the corresponding modal, as well as the different excitations frequency response characteristics under force. The results showed that themotion trajectories of the end-effector of the theoretical and the simulation model were basically the same, and they were also consistent with the natural frequencies of the vibration simulation model, which verified the correctness of the simulation model. As the amplitude of the excitation force increased, the system response was increased. Corresponding to the same excitation frequency, the Y-direction response at the center of mass of the moving platform was the strongest, followed by the X-direction, and the Z-direction was the smallest. Among them, the system corresponding to the 11th to 12th modes had the largest deformation, and the corresponding excitation frequency was 40~60Hz.