Abstract: Objectives Thermodynamic analysis and optimal design of the electrolytic water hydrogen production system for offshore wind power are carried out to study the effects of operating pressure, operating temperature and lye flow rate on the operating characteristics of the system. Methods Thermodynamic, kinetic and flux balance analyses were carried out to develop a thermodynamic equilibrium model for hydrogen production by alkaline water electrolysis (AWE) using Aspen Plus software, which was validated in comparison with literature results. Results The results show that the optimum working pressure and temperature of the alkaline water electrolysis hydrogen production system of this scheme are 9 bar and 70°C, respectively, and the optimum lye flow rate is 1600 t/h. The system energy loss and yield loss increased with the increase of input current density.When the AWE input current density was 3000A/m2, the system energy efficiency and yield efficiency were 63.58% and 57.27 %, respectively, and the system energy loss accounted for 26 % of the total energy input, of which the yield loss of the electrolyzer was the highest, which accounted for 93.39 % of the total yield loss of the system. Conclusions Through this parameter optimisation method, a suitable range of operating parameters can be obtained, which can provide a reference for the selection of offshore wind power hydrogen production parameters.