Abstract: Based on the convenient normalization heat treatment process for the SA106C steel tube,the isothermal normalization process is presented. And a comparative analysis is made to the metallographic structure and the mechanical properties of the SA106C tube as treated with the convenient normalization process and to those of the same tube as treated with the isothermal normalization process. The analysis result shows that compared with the convenient normalization process,the isothermal normalization process makes the tube much better in terms of structure and property,i.e.,the grain structure is finer with grain size enhanced by 2. both the yield strength and tensile strength are increased by about 30 MPa,the impact toughness is also a little bit increased,and the comprehensive mechanical properties of the material are good.