Abstract: In order to study the effects of different mixing ratio and silage preparation combination on the quality of alfalfa and sweet sorghum wrapped mixed silage, alfalfa and sweet sorghum were used as raw materials, and mixed ensilage was carried out according to the ratio of fresh weight to mass of 100∶0（A1 S0）, 75∶15（A3 S1）, 50∶50（A1 S1）, 15∶75（A1 S3） and 0∶100（A0 S1）. Each proportion was treated with three silage preparations（0.01 g/kg lactic acid bacteria LAB, 0.005 g/kg cellulase E, 0.01 g/kg lactic acid bacteria+0.005 g/kg cellulase LE treatments）, and zero addition control（CK） treatment. After 60 days of silage, the nutrient composition, fermentation quality and aerobic stability of the packaged silage were determined. The results showed that when the silage preparation was the same, with the proportion of alfalfa in the mixture decreased and the proportion of sweet sorghum increased, the contents of dry matter and crude protein in each additive treatment showed a general trend of decrease, while the contents of neutral detergent fiber, acid detergent fiber and soluble carbohydrate showed a general trend of increase. When the mixing ratio was the same, the contents of dry matter, crude protein and soluble carbohydrate in the LAB, E and LE treatments were higher than those in CK treatment, and the contents of neutral detergent fiber and acid detergent fiber were lower than those in CK treatment mainly（except the neutral detergent fiber in the LAB treatments with the mixing ratio of A1 S0,the acid detergent fiber in the LE treatments with the mixing ratio of A1 S0 and the acid detergent fiber in the LAB treatments with the mixing ratio of A0 S1）. Soluble carbohydrate content was greater than 6% only in the A1 S3 mixture ratio E and LE treatments, and A0 S1 mixture ratio LAB, E and LE treatments. When the silage preparation treatment was the same, with the proportion of alfalfa in mixed raw materials decreased and the proportion of sweet sorghum increased, the pH value, ammonia nitrogen/total nitrogen, propionic acid and butyric acid contents showed a general decreasing trend; the lactic acid content showed a general increasing trend, and the acetic acid content did not change regularly. When the mixing ratio was the same, the pH value and ammonia nitrogen/total nitrogen in the LAB, E and LE treatments were lower than those in the CK treatment, and the content of lactic acid was higher than that of CK treatment. The pH value in the LE treatment was the lowest, and the lactic acid content was the highest. The interaction of mixing ratio and silage preparation had significant effects on the contents of soluble carbohydrates, lactic acid, propionic acid and butyric acid, and aerobic stability（P＜0.01）, and had significant effects on the contents of neutral detergent fiber and acetic acid（P＜0.05）. The effects of mixing ratio on all nutrient composition indexes, fermentation quality indexes were extremely significant（P＜0.01）. The silage preparation had significant effects on dry matter content, pH value and acetic acid content（P＜0.05）, and very significant effects on other nutrients, fermentation quality indexes（P＜0.01）. These results indicated that the lower the proportion of alfalfa and the higher the proportion of sweet sorghum was, the lower the feeding value of silage has, but the better the fermentation quality was. The addition of lactic acid bacteria and/or cellulase could improve the nutrient composition and fermentation quality of silage to varying degrees. In summary, it is recommended to use 0.01 g/kg lactic acid bacteria + 0.005 g/kg cellulase as the silage preparation, and to ensilage alfalfa and sweet sorghum at the fresh weight ratio of 25∶75.