Abstract: Objective In this paper, functions and safety of casein were study through mice trial, so as to establish a new BDI-GS comprehensive assessment system and method for nutrition, health-promotion and safety of foods. Method ICR mice during growth were fed for 12 days with the low-nutrient maize diet and casein blending diets. Observe body weight, organ weights, organ indexes andits effects benefit-damage Index (BDI) of mice to assess nutrition, health promotion and safety of casein. Results The present study manifests that casein possesses significant comprehensive nutrition effects, and better health-promotion and prevention effects for declining immune function and Type II diabetic mellitus. Conclusion The present study establishes an easy, intuitive and comprehensive new system to assess food nutrition, health-promotion and safety. This method can also be utilized to assess functions and safety of various other foods.