The fundamental principle and the structure of dielectric elastomer actuators, together with their applications in robotic systems were reviewed briefly, and the special stress was mainly laid on analyzing the progress in theoretical investigations on the properties of dielectric elastomer, including material characteristics, constitutive theory, failure mode and stability, etc. The actuator's specific requirements and the technique characteristics of the flexible electrodes were also summarized in detail. The application of dielectric elastomer actuators in robotic system was prospected on the basis of a profound discussion of the challenges that the dielectric elastomer actuators still have now.