Abstract: The relationship between Rockwell hardness and tensile strength of metal materials was studied by regression analysis. The results show that the relationship between Rockwell hardness x(HRC) and tensile strength y(MPa) can be expressed as y=496.55+14.704x. Rockwell hardness test is fast and simple under fixed production conditions. For some materials which cannot be tested by tensile test, Brinell hardness test and instrument indentation test, the tensile strength could be estimated by the regression equation obtained in advance.