Abstract: The optimal conditions of polypeptide chelated calcium were studied with the wasted beer yeast and eggshell as raw material.First of all, the wasted beer yeast after extrusion puffed pretreatment was hydrolyzed by papain, and taking the content of yeast polypeptide in the hydrolyzed liquid as indicator, the optimum enzymolysis conditions were determined as that liquid-solid ratio was 1 ∶20 (g/mL) , enzyme content was 15μL/g, enzymolysis time was 4h.Then the yeast polypeptides solution under previous optimized conditions was chelated with eggshell acid solution.Through single factor experiments and response surface analysis, the optimal chelate conditions were yeast peptides and eggshell acid solution volume ratio of 20 ∶1 (mL/mL) , pH value of 7.2, chelate temperature of 42.4℃, chelate time of 46min.Under these conditions, the chelate radio reached to 87.11%, which could provide a new way for improving the value of wasted beer yeast and eggshell.