Abstract: The rapid-opening valve is commonly found as an important component in an impulse wind tunnels, and its performance can directly influence the tunnel’s performance index. As one of hypervelocity launchers used in the the ballistic range, the high-pressure-gas-driven gas gun is a typical hypervelocity accelerating facility which uses the one- or multi- stage high pressure gas as the driven energy. The rapid-opening valve of a 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 within several milliseconds. This paper studies the design technology of the rapid-opening valve employed in the high-pressure-gas-driven gas gun. Firstly, the interior flow in the assembly of the gas chamber and the rapid-opening valve was studied by CFD simulation, then the influence laws of the structure and the opening rate of the valve on the interior flow were analyzed, to make sure of an ideal design of the interior gas corridor and opening rate of the valve. Secondly, this work develops the kinetic model of the rapid-opening valve, and investigates 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 is 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 were presented in the end. The tests measured the pressure curves behind the valve body during the opening processes when the gun was driven by three different gases of N₂, He and H_2, respectively, within the pressure range of 10−30 MPa. The test results show that the opening time of the DN25 valve is about 1 ms when driven by H₂ at the pressure of 30 MPa, and the gas-driven gun has developed the model launching capability up to 6.27 km/s.