With the development of the new power system and the implementation of the national "Double Carbon" goal, the development of the transmission grade vacuum switch to replace Sulfur hexa-fluoride (SF₆) circuit breaker has become a research hot-spot in this field, among which the driving system of the long gap vacuum switch is one of the difficulties in technical research. Based on the driving system of the Vacuum Interrupter Unit (VIU) in environment friendly GIS, the physical model, dynamic description and dynamics model of the dual-actuated of back-to-back VIU are established. Through the analysis of the opening and closing process of VIU electrodes, it can be seen that the dual-actuated system can share the demand for the opening speed of the long gap interrupter, and the collision impulse can be offset greatly during the closing process, the rebound amplitude and bouncing time of the contacts during the closing process can be greatly reduced, which can reduce the harm. Taking the closing process of 252kV vacuum circuit breaker as an example, the process of closing bounce and vibration is described, and the technical problems in the motion damping and the synchronization requirements of dual-actuated operation are discussed. In order to prove the analytical results of the physical model, the calculation model of VIU contact motion parameters based on ADAMS dynamic simulation software was established, and the relevant parameters of 252kV vacuum circuit breaker dual-actuated system were simulated and analyzed. The results show that the range and duration of the contact bounce during the closing process are significantly reduced. The comprehensive advantage demonstration using dual-actuated system needs further prototype measurement, and the guiding damping should be strengthened in practical application to reduce the synchronization error as much as possible. The dual-actuated 252kV VIU provides a new structure scheme for the transmission grade vacuum circuit breaker.