The work aims to propose a new variable universe fuzzy controller based on improved salp swarm algorithm to solve the problems of large steady-state error and poor anti-interference caused by the non-timely adjustment of PI controller parameters of permanent magnet synchronous motor, to improve the production efficiency of automatic packaging line. Through the migration strategy and variation distribution strategy, the position update of salp swarm intelligent algorithm was improved, and the weighted position correction of the crossing individuals and the secondary migration of the inferior individuals were introduced. The optimized algorithm was combined with variable universe fuzzy PI controller to adjust the contraction-expansion factor, so as to achieve better control effect of permanent magnet synchronous motor. The simulation results showed that the optimized controller had smaller offset than the traditional PI controller; meanwhile, it made PMSM respond faster in working conditions of variable speed and load. Compared with that before improvement, the overshoot of PI controller based on SSA was decreased by 21.35% and 62.85% respectively. Compared with other control, the variable universe fuzzy control obtained by the algorithm after optimizing the contraction-expansion factor can improve the robustness of the system more effectively, improve the control performance of the system, and reduce the loss in the process of variable speed.