Abstract: The traditional model of alkaline water electrolyzers（AWEs）is established based on electrochemical equations and only suitable for micro-electrolysis systems with a single electrolysis cell. However,for large-capacity AWEs used for hydrogen production from renewable energy,traditional models have great limitations and cannot fully describe operating characteristics in wide range. By analyzing the reaction process of the electrolyzers under different working conditions,this paper reveals the excitation mechanism of the external electric field for the reaction of the large-capacity AWEs and a new equivalent circuit model of the AWEs is proposed. It is found that the physical structure of the electrolytic cell has a more critical influence on the characteristics of the AWEs than that of the microscopic characteristics of the electrode material in wide range. Finally,based on the prototype of the self-made AWEs,experiment for hydrogen production is carried out. The results show that the model proposed in this paper can better describe the operating characteristics of the electrolyzers under different working conditions.