Ignition of hydrogen-air premixed gas in the vicinity of a hot surface has been investigated. Especially multistep reaction model was compared with a single reaction model. It was found that the multistep model with 48 step elementary chemical reactions produced a phenomenologically reasonable trend in ignition delays. The ignition d(2lays increase as the mixture becomes either fuel-rich or fuel-lean with a minimum near the stoichiometric value. The minimum surface temperature has been deduced by extrapolating predicted ignition delays. It was in quite good agreement with the experimental data.