Abstract: In a bid to product high -protein feed through double enzymatic degradation of cellulose and microbial fermentation, the citrus peel residue was chosen as the raw material by the superfine grinding technology of pretreatment. With the soluble protein and reducing sugar as examining index, the main impact factors including adding amount of pectase and cellulose, system pH, yeast inoculation quantity and cultivate time were investigated. The technological conditions of fermentation were optimized by orthogonal experiment. The results showed that the best technological conditions of fermentation were as follows: 0.06 g/100g of pectase and 0.02 g/100g of cellulose at 50益in pH 5.0 for 1 h, the citrus peel residue with efficacy reducing sugar and yeast exploitation degree was obtained. Then the citrus peel residue was cooled to 35益, inoculation quantity 10.0% (V/V), pH 4.0 and cultivate time 5 d were optimal for the increasing of protein content in fermentation production, the yield of soluble protein was 101.9 mg/L.