Three type of antioxidant with different concentrations were individually applied in the study of fat oxidation and color property of nature casings.The result showed;0.005%BHT,0.02%V_E and 0.005%sodium erythorbate had a good effect to inhibit fat oxidation and to protect color fading than other testing groups.Mixture design methodology was used to optimize antioxidant composites formula,the proportion of every antioxidant were limited in the range of 0.005%to 0.01%.The regression model of relationship between proportion and color rate of K_(δE) was also established.The result were that treated with the combination of 0.005%BHT,0.01%V_E and 0.005%sodium erythorbate,K_(δE) was the smallest and casing's color was the best.