The characteristics of the flame propagation in inert particles laden $H_2$/Air premixed gases are numerically investigated on this study. The 2nd order TVD scheme is used for numerical analysis of governing equations. And a multi-step reaction model and a detailed transport properties are applied by using CHEMKIN program when solving chemical reaction terms. Radiative heat transfer is computed by applying the finite-volume method to radiative transfer equation. The burning velocities for mole fractions of hydrogen in $H_2$/Air premixed gases agree well with results performed by different workers. As a result, the inert particles play significant roles in the flame propagation according to the loading ratio of particles. Gas temperature, pressure and flame propagation speed are decreased as the loading ratio of particles is increased on account of momentum and heat transfer between gases and particles. Also, particles not only emit and absorb radiation but also scatter it and the products behind flame zone contain lots of water vapor whose absorption coefficient is much larger than that of other gases. Thus radiative effects for water vapor and particles must be considered simultaneously for the flame propagation in particle laden $H_2$/Air mixture. It is founded that because the water vapor emits much radiation and this emitted radiation is released at the boundaries as a radiative heat loss as well as reabsorbed by gases and particles flame propagation speed, gas temperature and pressure are altered when the flame propagates.
