In this study, the specific reasons for pincushion distortion during the scanning process of galvanometers are analyzed. A complete mathematical model of the galvanometer-scanning system is established based on theory and principle, and an algorithm for reverse compensation of the driving voltage is proposed to solve the pincushion distortion problem. The proposed algorithm expresses the relationship between the scanning path and the deflection angle of the galvanometer, presents simulation results of the intermediate voltage compensation process, and derives the correction formula of the galvanometer-driving reverse voltage compensation algorithm. The correction amount of pincushion distortion is presented in a simulation form. The simulation and experimental results demonstrate that the proposed algorithm can effectively correct pincushion distortion, thereby improving the accuracy of the galvanometer scanning system and satisfying the requirements for practical applications.