Abstract: In this paper,a numerical study is conducted to investigate the possible high pressure hydrogen leakage during the refueling process of hydrogen powered vessels. The virtual nozzle model and flow partitioning model used in the CFD simulation for the leakage are verified by comparing with existing experimental results. The effects of wind speed and obstacles on the high-pressure hydrogen diffusion behavior were analyzed based on actual refueling scenarios of hydrogen powered vessels. The hemispherical diffusion model is used to determine the evacuation area to improve the safety during the refueling process. The results show that the performance of the flow partitioning model is better. The high-speed wind can prevent the hydrogen from floating,increase the hydrogen leakage distance and reduce the hydrogen concentration. The obstacles placed downstream of the leakage location can shorten the diffusion distance of flammable clouds in the horizontal direction to a certain extent.