Abstract: The objective of this study was to investigate the optimum preparation method of biological feed with grape pomace fermented by co-culture of Candida utilis and Lactobacillus acidophilus.Using true protein content of the fermentation products as evaluation index,the optimal fermentation conditions were screened by orthogonal experimental design method.The results showed that the optimum inoculation ratio of Candida utilis and Lactobacillus acidophilus was 1.5∶1.0 and the optimum inoculation amount was 10.0%;the formula of the solid fermentation medium were as followed:grape pomace 75%,auxiliary material 25%(corn∶wheat bran=1∶1),urea 1.5%,ammonium sulfate 1.5%,magnesium sulfate 0.4%,and potassium dihydrogen phosphate 1.5%;the optimum fermentation conditions were as followed:the quality of fermentation material was 100 g/500 mL,material-water ratio was 1.0∶1.0,fermentation at 32℃for 72 h with nature pH value.Under this condition,the true protein content of final fermentation products was 14.45%(dry matter),which was 4.35%higher than the raw material.Our results provide new ideas for feeding utilization of grape pomace and development of application of novel feed resources.