Abstract: To improve the hydrogen production efficiency of electrolytic hydrogen production system under highly fluctuating operating conditions， an efficiency enhancement method based on the synergistic optimization of temperature and pressure was proposed. First， by decoupling the temperature-sensitive parameters of the proton exchange membrane electrolyzer， electrochemical and system efficiency models suitable for high current densities and a wide temperature range were established. Then， the influence mechanism of operating temperature and cathode pressure on system efficiency under varying input power was analyzed by using the developed model， and the temperature-pressure synergistic optimization strategy was formulated. Finally， the simulation model of an off-grid wind-powered hydrogen production system was built in order to validate the proposed method. The results showed that， compared with the constant temperature and pressure strategy， the overall system efficiency was increased by 3.29 percentage points， the daily hydrogen production was increased by 3.68%， and the average anode hydrogen content was reduced from 12.97% to 4.93% by the proposed synergistic optimization strategy. Moreover， by optimizing the input power ramp rate， the maximum anode hydrogen content was further reduced by 5.15 percentage points.