Abstract: Rapid-opening valve is commonly found as an important component in impulse wind tunnel, and its performance can directly influence the tunnel’s performance index. As one of hypervelocity launchers used in ballistic range, the high-pressure-gas-driven gas gun is a typical hypervelocity accelerating facility which uses one- or multi- stage of high pressure gas as driven energy. The Rapid-opening valve of high-pressure-gas-driven gas gun is a conical valve which controls the fast release of the high pressure gas in the gas chamber, and it is required to realize the valve opening in several milliseconds. This paper studied the designing technology of Rapid-opening valve employed in high-pressure-gas-driven gas gun. First off, this work studies the interior flow in the assembly of gas chamber and Rapid-opening valve by using the CFD simulation methodology, then analyzed the impact laws of the structure and the opening rate of the valve on the interior flow, to make sure of an ideal design of interior gas corridor and opening rate of the valve. Second, this work developed the kinetic model of the Rapid-opening valve, and investigated the valve characteristics of the opening acceleration, speed and displacement under different loading conditions through numerical simulation of the kinetic model. The design optimization of the valve structure was carried out through the iteration of multiple parameters. The test applications of the millisecond Rapid-opening valves of DN25 and DN100 in two-stage light-gas guns was presented in the end. The tests measured the pressure curves behind the valve body during the opening processes when the gun was driven with three different gases of N₂, He and H₂ within the pressure range of 10～30 MPa. The test result shows that the opening time of the DN25 valve is about 1 ms when driven with H₂ at the pressure of 30 MPa, and the gas-driven gun has developed the model launching capability up to 6.27 km/s.