This study provides a type of soft vacuum-actuated rotary actuator. The structures in the actuator are based on different elastomeric structures that comprise a number of interacting elastic radial beams, elastic circumferential beams, and interconnected, deformable sector ring structure air chambers. When negative pressure is applied to the structure, the radial beams bend reversibly into serpentine shapes until adjacent circumferential beams contact each other. This bending results in a large change in the circumferential angle of the structure, but a smaller change in its radial width. Thus, the structure produces rotational motion in its circumferential direction. The design, fabrication, and mechanical analysis of the actuator are introduced, respectively. Moreover, finite element simulation analysis and experimental testing are carried out to study the corresponding relations between the air pressure, rotation angle, and force of the actuator. In addition, the stimulation results and the experimental results of the actuator are statistically analyzed by statistical product and service solutions (spss) statistical software. The test results of the experimental platform are highly correlated with the results of the finite element simulation.