The kinetic model of flexible pneumatic torsion (FPA) joint was established based on equilibrium of moments, and the dynamic models for inflating and deflating process were built based on adiabatic gas conservation of energy. The influences of FPA initial shell-thickness, average radius, initial angle, and connector outlet area on the dynamic characteristics of torsion joint were analyzed. Simulation results showed that the initial shell-thickness, average radius and initial angle of FPA influenced both the turning-angle and dynamic process of torsion joint, while the connector outlet area had no effect on the turning-angle and dynamic process. Experimental results were close to that of simulation, which implied that the established model of flexible pneumatic torsion joint could fairly describe its dynamic process and characteristics. 