OBJECTIVE：To investigate the quality differences of Betamethasone tablet from different enterprises， and provide reference for the eventual establishment of the drug relative quality evaluation system. METHODS： According to the principle and steps of the ideal point method， a mathematical model was established. And the perfect point of the 3 inspection parameters （content， content uniformity and dissolution） of Betamethasone tablet was regarded as the upper limit theoretically， and the permissible point as the prescribed minimum in the model. After homogenizing the initial data or ones to be quantifiable were translated into evaluation parameters；and the evaluation parameters were calculated by ideal point method to receive comprehensive evaluation results. RESULTS： According to variance analysis， there was no significant difference in the comprehensive evaluation results of Betamethasone tablet from different enterprises（P＝0.54＞0.05）， indicating that the overall quality of Betamehasone tablet was good. CONCLUSIONS： The mathematical model of quality evaluation with different drug has certain feasibility and operability.