The rotary joint actuated by dielectric elastomer has advantages to fabricate a biomimetic soft robot because of the large output torque, deformation and light weight. Conventional rotary joint actuated by dielectric elastomer is difficult to meet the requirements due to its small output torque. This paper proposes improved fabrication process and structure which can increase comprehensive performance. From experiments, the improved design had a maximum output moment of 14.21mNm which was almost 2 times that of the conventional design, its voltage-induced deformation angle was improved 5 degrees and weight was decreased too. The improved rotary joint will benefit load capacity of the soft robot actuated by dielectric elastomers.