Abstract: In response to the dual-carbon target and the hydrogen-energy-development planning and strategies, combined with solar photovoltaic-thermal (PV/T) technology and proton exchange membrane (PEM) electrolysis hydrogen production technology, a photovoltaic-thermal electrolysis hydrogen production model was proposed using PV/T power supply and preheating electrolytic water supply. The PEM electrolyzer components were established and the system model was constructed in TRNSYS software for transient analysis. Then, it was compared with a non-preheating system under the same conditions. Results show that preheating affects the temperature rise and fall of the electrolyzer and makes the electrolyzer work at a higher temperature, which improves the efficiency and increases the hydrogen production.The gain effect of preheating on the temperature, efficiency and production is more obvious under weather conditions with low electrical power or strong radiation fluctuations.The efficiency of the system's solar hydrogen production is around 12%, and the annual hydrogen production is 8 003.08 m³, which is 24.11 m³ more than that of the none preheating case, with a growth rate of 0.30%.