Hot-rolled ribbed steel bar (HRB), as a main structural material, plays an irreplaceable role in many fields. Chemical components of HRB directly influence basic mechanical properties. Through partial correlation analysis, we establish linear regression and polynomial regression models (quadratic and cubic) of tensile strength and chemical components of HRB400 in China. So we can control the production of HRB400 to ensure the mechanical properties by adjusting the contents of chemical components