Abstract: A three-dimensional numerical model integrating electrochemical processes with gas-liquid two-phase Euler–Euler turbulent flow is developed, considering the collision forces caused by gas-liquid two-phase distribution at the microscale within an industrial filter-press alkaline electrolyzer. The individual and coupled effects of electrolyte flow rate, temperature, and concentration on the performance of the electrolyzer are systematically investigated. The results indicate that bubble accumulation along the flow channel reduces current density and causes uneven electrode utilization. Increasing the electrolyte flow rate to 0.25–0.30 m/s enhances turbulence, facilitating bubble detachment and improving current density; however, excessively high flow rates significantly increase the risk of equipment corrosion. At temperatures between 60 and 70 ℃, the positive effects on electrolyte conductivity and ion transport significantly enhance current density, which peaks within this range. Conversely, temperatures above 70 ℃ induce performance degradation due to bubble accumulation. At a KOH concentration of 6–7 mol/L, an optimal balance between electrolyte conductivity and ion transport efficiency is achieved, yielding the most uniform current density distribution. Multi-parameter coupling analysis further reveals that a high flow rate can effectively suppress the negative effects caused by high temperature or high concentration, significantly improving current density. In contrast, the combination of high temperature, high concentration, and low flow rate leads to a sharp performance deterioration due to the synergistic effects of bubble curtain and ion blockage. These findings elucidate how gas-phase distribution and individual and synergistic effects of operating parameters influence electrolyzer performance, providing theoretical guidance for optimizing the design and operation of filter-press alkaline electrolyzers.