For replacing the presently employed pickling method with a more environmentally friendly descaling method,hydrogen reduction of oxide scale formed during hot rolling was studied at 800 ℃ under a varied atmosphere.The hydrogen level and water vapor content in the reducing atmosphere were found to influence the reduction rate wherein increasing hydrogen level as well as decreasing water vapor content resulted in faster oxide reduction. The reduction reaction substantially obeyed a parabolic rate law. Oxide scale of a usual thickness( approximately 7micrometer) could be reduced almost completely in an atmosphere of 20 vol. % hydrogen with a water vapor content corresponding to a- 40 ℃ dew point at 800 ℃. When lowering the hydrogen level to 10% and increasing the water vapor content to a 10 ℃ dew point,quite a large extent of the oxide scale was retained,which might be attributable to the formation of an outermost dense layer of pure iron at the early stage of reduction. For replacing the presently employed pickling method with a more environmentally friendly descaling method, hydrogen reduction of oxide scale formed during hot rolling was studied at 800 ℃ under a varied atmosphere. Hydrogen level and water vapor content in the reducing atmosphere were found to influence the reduction rate so increasing hydrogen level as well as decreasing water substantially decrease in parabolic rate law. Oxidation scale of a normal thickness (approximately 7micrometer) could be reduced almost completely in an atmosphere of 20 vol .% hydrogen with a water vapor content corresponding to a- 40 ° C dew point at 800 ° C. When lowering the hydrogen level to 10% and increasing the water vapor content to a 10 ° C dew point, quite a large extent of the oxide scale was retained, which might be attributable to the formation of an outermost dense layer of pure iron at the early stage of reduction.