Compared to other spinning system, the ring spinning process has been used to produce higher quality yarns, but with a much lower spinning efficiency, resulted from the relatively high spinning tension that leads to increased yarn breakage rates and makes high power consumption. Thus, depressing yarn tension is essential to change the status. In this paper, we design a movable balloon controller system to reduce yarn tension. The system is automatic, composed of powder switch, touch screen, PLC (Programmable Logic Controller), pulling-thread displacement sensor, controller of step motor, step motor and linear module. PLC, the core of the system, controls the position of the balloon controller by a series of programs. Then yarn tension was tested while spinning with movable balloon control ring, fixed balloon control ring and no balloon control ring, respectively. The result shows that the yarn tension can be depressed indeed by equipping this movable balloon controller system to some extent. Additionally, we find that the number of hairiness of ring spun yarns with this system can be reduced to some extent, while yarn tensile properties are not as sensitive to be worse. It is significant to cut down ends-down rate, improve the quality of ring spun yarns, the spinning efficiency as well as the energy efficiency of ring spinning.