<p>The metrological comparison of reference materials at the multiple levels of quantity value is a relatively complex mode of metrological comparison. To study the determination of comparative reference equations and the calculation method of degree of equivalence, taking the data from CCQM-K80 “Comparison of value-assigned CRMs and PT materials: Creatinine in human serum” comparison project of the Consultative Committee for Amount of Substance (CCQM) as an example, while considering both the uncertainty of reference materials and the uncertainty of comparison measurements, a generalized distance regression method is used to determine the comparison reference equation and obtain the comparison reference values and uncertainties of reference materials at different levels of quantity value. Based on the certified values and uncertainties of reference materials, comparison measurement values and uncertainties, and corresponding comparison reference values and uncertainties, combined with comparison reference equations, the Monte Carlo method is used to the calculate degree of equivalence and uncertainty. Compared to <i>ζ</i>, using generalized distance regression to determine the reference equation and then calculate the degree of equivalence and uncertainty, the calculation results are more comprehensive, integrating information such as reference material quantity values, comparison measurement results, and comparison reference values.</p>