As an important factor in composite fiber winding, fiber winding tension influences the product quality directly, and therefore tension control is a key technique in fiber winding techniques. This paper introduces a closed loop tension control system with the PIC single chip computer as the kernel, a function module with TLC5615 D/A converter as the output, AC servomotors as the actuator, and a radius-following arm to measure the real time radius of the scroll. The mechanism of the tension control system is analyzed and the mathematical model is set up. Then the paper expatiates the design of main control circuit, the voltage transformation circuit and the analogy filter circuit. In addition, the paper presents digital filter and control algorithm of the PIC software. The system is proved to have high control precision and rapid time response through performance experiments of the tension control system in different working states, which well meets the anticipated design requirements.