Abstract: Surplus wind power is adopted for hydrogen production in a wind-power-coupled-with-hydrogen system, effectively improving the wind power consumption capacity. The alkaline water electrolyzer is an essential component of the wind-power-coupled-with-hydrogen system. Study of electrolyzer's operating characteristics by numerical methods is crucial to improving hydrogen production efficiency. However, existing models usually focus only on its electrical performance, causing it hard to predict the cell's states under various environments. Therefore, we proposed a multi-physical model of electric, flow and concentration field of an electrolyzer. Firstly, the geometric modeling of the electrolyzer was carried out; then the mathematical models of electric, flow and concentration field were established, and the electrolyzer model was built based on COMSOL. After verifying the validity of this model, the effects of voltage, current, temperature, pressure, electrolyte concentration and flow rate on cell's steady-state and transient operating characteristics were analyzed. The simulation results reveal that higher temperature and lower pressure will reduce the voltage required per unit current; the efficiency is increased by reducing the current and increasing the temperature and pressure. The voltage required per unit current will ascend and then descend with increasing concentration; the efficiency increases and then decreases with increasing concentration, and the KOH solution with a weight percentage of 30% at 50 ℃ has the maximum efficiency. The sudden voltage variation will cause a current overshoot, while the sudden variation of flow rate will not. The research results can provide theoretical guidance for electrolyzer design and operation performance prediction.