In order to meet the requirements of different flight missions, the flexible wings of the foldingwing aircrafts can be folded or deployed during the flight. As one of the key aspects of foldingwing aircrafts, successful deployment and locking of the folding wings matters. Hence, in this work, the passive deployment dynamics of a hypersonic folding wing is studied. An accurate dynamic model is established and the parameters for deployment is investigated for the purpose of reducing the shock vibrations of the folding wing after deployment. Firstly, a flexible multibody dynamic model of the folding wings is established via the absolute nodal coordinate formulation (ANCF), which can accurately describe the large rotations and large deformations of the folding wings. The piston theory is utilized to derive the aerodynamic forces of the folding wing during deployment. The generalized α algorithm is used to solve the system dynamic equations. Secondly, the influence of the deployment torsion bar, the retarding spring, and the flight attitude on the dynamic response of the folding wing is studied. The system parameters are optimized to effectively reduce the shock vibrations of the folding wing.