In order to improve the safety of the wind tunnel test, the flexible dynamics of a 6—PSS parallel mechanism for the wind tunnel was analyzed. At first, inverse kinematics of the parallel mechanism was received based on the analysis of its kinematics, and Jacobian matrix was calculated by using the first-order influence coefficient method. Then, the dynamics equation was solved by using the Lagrange equations and a simplified rational dynamics method. A simple and practical method of flexible dynamic simulation was put forward. The flexible dynamic simulation of the parallel was obtained with ADAMS software. The correctness of flexible dynamics simulation was verified by comparing the kinetics and dynamics date form rigid and flexible analysis. At last, the character of flexible kinetics was summed up by analyzing the driven force and flexible deformation data.