Hydrogen production from wind-solar generation is of great importance for consuming renewable energy and it is meeting industrial hydrogen demand. In this paper, the modelling of the off-grid hydrogen production system from wind-solar generation and the simulation of its operating characteristics are investigated. Firstly, the network architecture and hierarchical control architecture of the off-grid hydrogen generation system are designed with the goal of efficiently utilising wind-solar generation output. Then, the components of the off-grid hydrogen generation system are characterised and modelled. Finally, the operating characteristics of the hydrogen production system under three operating conditions, such as hydrogen system startup, wind power fluctuation, and electrolyzer partial failure are simulated and analyzed, revealing the ability of the alkaline electrolytic water hydrogen production system to respond to the fluctuation of wind and solar power.