The potential hazard of cryogenic and combustible liquid propellants (hydrogen and methane) leakage caused by spontaneous damage of tanks or rupture of pipelines is still a problem for both applications and human beings. Numerical simulations have been performed to predict the fuels' leakage and dispersion behavior differences. Based on liquid hydrogen release tests conducted by the Health & Safety Laboratory (HSL), a mixture four-phase flow model considering the liquid hydrogen and air phase transitions has been developed. The liquid phase movements in the near field, combustible clouds and cold effect clouds movement in the far field were investigated. With Froude number increases from 0.47 to 3.72, liquid hydrogen represents a downward trend while liquid methane shows a downwind trend. For combustible clouds, the movements of hydrogen are larger than that of methane in both downwind and vertical direction on a quasi-stable state. For cold effect clouds, the dispersion of methane is greater than that of hydrogen in Froude number of 0.47, 0.93, 1.86, but then smaller in larger Froude number of 3.72. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.