A rotational joint has been designed and fabricated by making use of the advantages of the dielectri electro active polymer (EAP) material.On the basis of dielectric EAP’s deformation theory,a cylindrical actuator has been designed and manufactured.The maximum displacement of 11 mm has been attained and the elongation strain of active area has been up to 33.8%.Also,the actuator’s output force’displacement characteristics have also been tested.The rotational joint driven by this type of actuator can achieve the rotation angle of about ±13°,and the torque of 19.6 mN·m.The rotational joint has been used to a crawling robot,and the experiment result has been analyzed.