Servo motor is the main link of driving,controlling and mechanical transmission of the wire harness terminals assembly equipment,the quality of its control system determines the performance of the equipment.Combining the structure and working principle of the equipment,a control mathematical model was established for the important servo system of the equipment.In order to obtain better controller parameters,the particle swarm optimization (PSO) search optimization was improved,and the PID controller parameters were optimized through PSO,and the optimized PID controller was used to design multi-motor power balance control strategy.The simulation verification shows that the improved particle swarm algorithm can realize the multi-motor power balance control effectively,with the changing of load,the control strategy can control the output of each motor to achieve a balanced load distribution.