Focused on the difficulty in maintaining a constant value of the warp tension in trawl fishing, fuzzy-control and PID control system is designed and set up to achieve constant tension. Based on the driving principle of the trawl winch, the transfer function of the warp constant tension control system is established, then fuzzy PID controller is constructed to adjust the warp tension by controlling the speed of trawl winches. The structure of the hardware and software is described and the result is simulated by Matlab. The simulation result shows that warp tension will reach a constant value in 0.8s by using fuzzy PID control system and will return to the previous stable state in 0.7s after receiving the interference, which is better than the traditional PID control and fuzzy control. Research shows that the Fuzzy PID control system has the characteristics of fast response, small overshoot, and strong robustness and so on and maintains the warp tension constant effectively for constant tension control system of fishing boats trawling winch, which will improve the fishing efficiency and has a great significance in guiding practice.