In order to study the dynamic characteristics of the wave-tilt-dam mechanical seal under perturbation,based on the fluid lubrication theory and the small perturbation method,the perturbation film pressure control equation including the boundary conditions of the JFO was established considering the liquid film cavitation.The dynamic stiffness and damping coefficient of the liquid film on the seal end face under three degrees of freedom perturbation was numerically solved,and the influence of geometric parameters and operating parameters on the dynamic characteristic coefficient of the wave-tilt-dam mechanical seal was analyzed.The results show that as the medium pressure increases,the dynamic stiffness and damping coefficient of the liquid film increases,which is beneficial to improving the dynamic stability of the seal.Although the dynamic stiffness coefficient of the liquid film increases at high speed,the damping characteristic of the liquid film becomes worse,and the operation of the sealing condition is prone to instability.As the amplitude coefficient increases,the dynamic stiffness and damping coefficient of the liquid film increases.When the wave number is about 8 and the dam width ratio is about 0.25,the dynamic stiffness and damping coefficient of the liquid film can be relatively optimized.