Abstract: To address the unclear hydraulic interference propagation mechanism and the challenge of optimizing control strategies in complex water conveyance systems for pumped storage units, this study constructs a mathematical model of a one-pipe-two-unit pumped storage power plant based on the method of characteristics and full characteristic curves. The influence of water conveyance system structural parameters on hydraulic interference stability is investigated. The results indicate that selecting the unit corresponding to the branch pipe with a larger water flow inertia time constant Tw as the interference unit can reduce the impact on the disturbed unit. Further extending the analysis to a one-pipe-four-unit system reveals that using two units on the same water conveyance branch as interference units can reduce the maximum rotational speed of the disturbed unit. Finally, a governor parameter optimization model is developed based on the NSGA-III algorithm and the TOPSIS decision-making method. The optimized guide vane control strategy reduces the speed regulation time by 10.59% and 12.57% for the one-pipe-two-unit and one-pipe-four-unit configurations, respectively. These findings provide theoretical guidance for improving the hydraulic interference stability of pumped storage power plants operating within complex water conveyance systems.