A numerical model for dispersion of hydrogen in hydrogen powered automobiles was established basing on finite element method with species transport and reaction module of FLUENT. And corresponding numerical simulations were done in order to analysis the dispersion of hydrogen due to leakage from different position of the storage cylinder on the automobiles. Also, the distribution of the hazard region due to hydrogen dispersion was obtained. The simulation results show that the baffle above the cylinder can accumulate the hydrogen. Therefore, the high concentration region of hydrogen exists near the baffle. The study can provide reference for hydrogen sensor placement and safety design of hydrogen powered automobiles.