To optimize the electroosmotic method, we investigated the consolidation effect of soft soil under various potential gradients and conducted a comprehensive analysis of energy consumption. Six groups of potential gradients (1.00, 1.25, 1.50, 1.75, 2.00, 2.25 V/cm), denoted as V1 to V6, were set up. We comprehensively analyzed the optimal potential gradient for electroosmotic reinforcement of soft soil by comparing the drainage ratio, contact resistance, and average energy-consumption coefficient during electroosmosis, along with the water content, bearing capacity, and shear strength after electroosmosis. The results indicate that, except for V1 and V2, there were negligible differences in the drainage ratio and final water content of the soil after electroosmosis. However, in the later stage of power-on, the contact resistances of V1, V3, and V6 increased by 15.76, 25.65, and 35.39 times respectively, and the average energy-consumption coefficients increased by 5.07, 6.12, and 10.98 times respectively. The soil strength of all groups increased with the rise of the potential gradient. Specifically, the average bearing capacity of the V1-V6 soils increased by 2.79-4.89 times, and the average shear strength increased by 5.7-12.2 kPa. This is mainly because the soil can consolidate rapidly under a high potential gradient. Therefore, without considering energy consumption, the optimal potential gradient ranges from 2.00 to 2.25 V/cm. However, when energy-saving is taken into account, the optimal potential gradient lies between 1.50 and 2.00 V/cm.