The paper aims to research the method of online parameter adjustment to overcome the shortcomings of traditional PID control in pulp consistency control system with large time delay and non-linearity and the difficulty of parameter adjustment. Based on traditional PID control and in combination with quantum particle swarm optimization (QPSO) bionic algorithm, this paper proposed a traditional PID controller parameters optimized by QPSO and applied it to pulp concentration control system. At the same time, the basic QPSO algorithm was improved by introducing crossover operator, and the control algorithm was applied to pulp concentration control. The system was compared with traditional control. The result showed that compared with the traditional PID control and the basic quantum particle swarm optimization (QPSO) PID, the improved optimization algorithm could achieve more satisfactory control effect. The system had the advantages of small overshoot, fast response speed and high robustness. Pulp consistency control system based on improved quantum particle swarm optimization algorithm can effectively control pulp consistency, significantly improve the control accuracy and other performance indicators of the system, and better meet the requirements of practical application.