With increasingly serious environmental problems, energy structure transformation has become an inevitable trend. Using renewable energy to generate hydrogen is an effective way to achieve green electricity to produce green hydrogen. This paper takes photovoltaic (PV) off-grid hydrogen production system as the research object, analyzes the typical structure of the system, and establishes the mathematical model and simulation model of PV array, electrolyzer, PV converter and hydrogen production power supply. The control strategy of the system is designed, PV output power is controlled by maximum power point tracking (MPPT), and multiple PV modules are connected in parallel with master-slave control. Based on MATLAB /Simulink, three typical scenarios of steady operation of the system, increase of PV power generation and decrease of PV power generation are selected for simulation analysis. The simulation results show that the PV off-grid hydrogen production system established in this paper can produce hydrogen stably.