Abstract: The needle bar and the thread-taking-up mechanism are the main mechanism to form the thread trace of the embroidery in computerized embroidery machines, exerting great impact on the forming of high quality thread trace of the embroidery. This paper deals with the study of the cylinder spiral spring of the periphery cam with flat-bottomed pusher style thread-taking-up mechanism in computerized embroidery machines, it deduces the theoretic design equation while maintaining the movement regularity of the original thread-taking-up mechanism and gets the mechanics parameter as well as the geometric dimensions of the cylinder spiral spring. The cylinder spiral spring is assembled to the new model thread-taking-up mechanism in computerized embroidery machines, and the experiment is finished on computerized embroidery machines, it proves that the cylinder spiral spring of the new model thread-taking-up mechanism in computerized embroidery machines can satisfy the requirement of the thread-taking-up performance.