Since the aerodynamic center moving backward sharply in hypersonic flight ,the stability margin of the hypersonic vehicle increases largely while the maneuverability decreases .We proposed a novel method to solve this contradiction .We used relaxed static stability (RSS) to improve the maneuverability in hypersonic flight ,and de-signed the stability augmentation system (SAS) to ensure the stability in subsonic flight .Therefore ,the relation-ship between static stability and maneuverability was quantitatively analyzed in the first step ,and the numerical value of RSS was obtained on the premise of good maneuverability .Secondly ,the relationship between static sta-bility and aerodynamic parameters was quantitatively analyzed . We properly adjusted aerodynamic parameters based on the quantitative relationship to achieve the specific static stability set in the first step ,and therefore pro-vided the engineering realization methods .The vehicle will be statically unstable in subsonic flight with the specific static stability .Lastly ,SAS was needed to ensure the stability of the vehicle in subsonic flight .Simulation studies were conducted by comparing the linear SAS to the nonlinear SAS ,and the results showed that the nonlinear dy-namic-inversion controller can synthesize with proportional-integrall-derivative(PID) controller robustly and stabi-lize the hypersonic vehicle .