Objective In the beer filling process, changes of tank position will directly affect the quality and yield of beer. The key for the accuracy and stability of level control lies in the choice of PID parameters. Methods Targeting at the blindness problem of parameter selection for PID during the debugging process of the liquid storage tank liquid level, genetic algorithm was used for tuning the parameters of PID and the results were compared with the tuning results of the critical ratio method. Results The results showed that after tuning the PID parameters by the genetic algorithm, for the output response curve, the shortest rise time was 3.98 s, the minimum overshoot was 1.9% , and the shortest time of adjustment is 2.23 s. However, after tuning the PID parameters by the critical ratio method, the rise in the shortest time is 1.92 s, the minimum overshoot is 23.7%, and the shortest adjustment time was 3.98 s. Conclusion The overall result of the PID control parameter tuning based on genetic algorithm was better. For the output response curve, the shortest rise time was 3.98 s, the minimum overshoot was 4.2%, and the shortest adjustment time was 2.23 s, which met the control requirements.