Abstract: Here were introduced the welding residual stress and its elimination methods, and summarized the mechanism of heat treatment method to eliminate residual stress, process parameter design, characteristics of stress reduction heat treatment of low alloy steel, and the law of the effect of this treatment on the properties and residual stress of low alloy steel component. It was pointed out that, for the low alloy steel components, except for the stress relief reduction, it was necessary to avoid the material deterioration after stress relief heat treatment as far as possible in the process of material selection, production of the component and the formulation of heat treatment parameters.