A swaying joint was proposed based on the flexible pneumatic actuator (FPA), which was composed of two symmetrical and parallel-connected arc-shaped FPAs. The movable ends of arc-shaped FPAs were connected with the movable deck and the latter could sway around the revolving pair. By changing the air pressures inside the two arc-shaped FPAs, they would have turning angles with different sizes, which realized the swaying movement of the joint. The static model was established based on the equilibrium of moments. Simulation results showed that the turning angle of the swaying joint was basically linear with the air pressure inside the arc-shaped FPA. The turning angle increased with the initial angle, average radius of FPA and pre-stretching angle, and decreased with the shell thickness of FPA. Experimental results implied that the established mathematic model could basically describe the static characteristics of the swaying joint.