Abstract: In this article, taking the maximum relative principal curvature radius, the maximum coincidence degree and the minimum total volume of gear transmission as the optimization objectives, the multi-objective fuzzy optimization model of pure rolling single circular arc gear transmission mechanism is established by using the fuzzy evaluation method and multi-objective optimization design method comprehensively; then, the single objective analysis and multi-objective optimization design are carried out. The design analysis shows that the normal modulus has the greatest influence on the relative principal curvature radius of pure rolling single circular arc gear, followed by the number of teeth, the tooth profile coefficient, the helix angle and the tooth width coefficient. The number of teeth, the tooth width coefficient and the helix angle have great influence on the longitudinal coincidence degree, and it decreases accordingly with their increase. The normal modulus, the number of teeth and the tooth width coefficient have great influence on the volume of the gear, and it increases with their increase. The order of influence degree from high to low is as follows: the normal modulus, the number of teeth, the tooth width coefficient, the helix angle, and the tooth profile coefficient. The obtained results provide theoretical reference and basis for improving the contact performance and load-bearing capacity of pure rolling single arc gear, and reducing the volume of pure rolling single arc gear transmission mechanism.