The efficiency of ring spinning system has been limited by the yarn tension and the heat generated by ring/traveller. The dominant causes of yarn tension are 1) the force added directly to yarn by rotation of spindle and 2) the centrifugal force by yarn balloon which is generated by rotation of traveller. And the dominant causes of heat generation of traveller are 1) the friction between traveller and ring and 2) the friction between traveller and yarn. These primary factors cause and breakages of yarn and heat damages. In case of spun yarn manufacturing process for the PET(polyester) and nylon(thermoplastic material), the efficiency of the spinning system decreases above 10,000 rpm. Therefore a spinning system of a new concept which would clear the limitations mentioned above should be developed. The objective of this study is to design a rotating ring which has dynamic stability, high productivity and simple structure. The results of this study revealed that; 1) forty four kinds of rotating ring shape can be used, 2) the rotating ring of saw toothed supporting type has the largest value of moment of inertia ratio among the proposed ring shapes. 3) On the basis of the rotating ring of saw toothed supporting type, the shape of rotating ring has been optimized.