Abstract: Based on the characteristics of the discipline and the requirement of the undergraduates, we attempted to introduce the case teaching ＂Three-Step Method＂（case import, case analysis and case summary） to classroom teaching. We guided the undergraduates to think, analyze and summarize actively. The problems in the teaching process were analyzed and summarized. In this paper, we discussed how to apply case teaching method to Animal Nutrition Metabolic Disease teaching, so as to promote the teaching reform and improve the teaching effect. By implement of the ＂Three-Step Method＂, the theoretical and practical teaching was organically combined, the professional quality of the undergraduates was improved, and the interest and activity of the undergraduates for study was inspired.