Abstract: The dynamic characteristics of hydrostatic thrust bearings are influenced by the lubricating oil viscosity, oil film thickness, oil cavity area and other factors, and hydrostatic thrust bearing often withstands step load or sinusoidal load under extreme working conditions, and the sudden load will lead to change of dynamic characteristics, that is, the impact resistance of the bearing and the time required to restore the balance. In order to characterize the dynamics of the hydrostatic thrust bearing with double rectangular cavity under extreme working condition of high-speed heavy micro-gap, its dynamic characteristics were theoretically analyzed under different oil film thickness, lubricating oil viscosity, and oil cavity sizes. The influences of lubricating oil viscosity, oil film thickness and oil cavity area on the dynamic performance of the bearing under step load were also investigated. In further exploring the stability of the bearing under sinusoidal load, details on the dynamic changes of the oil film were revealed. Using the lubrication theory, mechanical control principles, and a theoretical research methodology, the influences of major oil film and design parameters on the dynamic performance of the bearing were derived, i.e. the influences of the viscosity of the lubricating oil, oil film thickness, and oil cavity size. The results show that the changes of the oil viscosity, oil film thickness, and oil cavity size have significant effects on the dynamic performance of the hydrostatic thrust bearing. The viscosity of the lubricating oil, the thickness of the oil film, and the area of the oil cavity are all positively correlated with the capability of the lubricating film to resist impact loading and the capability of the rotating table to maintain its equilibrium or recover its balance in a shorter time under high dynamic external loads. It is found that the oil film of the hydrostatic thrust bearing with double rectangular cavity has a larger damping coefficient with a high capability to resist sinusoidal loading.