Abstract: In order to analyze the quality of mixed silage of rice straw and corn straw with different addition ratios and to study its effects on dry matter intake and milk production performance of Holstein cattle, 25 Holstein cattle with 2-3 births, similar body weight, milk yield and production period were randomly divided into 5 groups（group Ⅰ, group Ⅱ, group Ⅲ, group Ⅳ and group Ⅴ）, with 5 cows in each group. On the basis of basic diet, rice straw and corn straw mixed silage with different fresh weight mass ratio（feed A0∶10, feed B1∶9, feed C2∶8, feed D3∶7 and feed E4∶6） were fed respectively. The pre-trial period lasted for 3 days and the pilot period lasted for 60 days. Field evaluation（color, odor, pH value, moisture content and texture） of mixed silage of rice straw and corn straw with different addition ratios was performed, its nutritional components（ammonia nitrogen and crude protein, crude ash, dry matter, neutral detergent fiber and acid detergent fiber） were analyzed, and the dry matter intake and milk production performance（milk fat rate, milk protein rate, lactose rate, total solid content, non fat solid content and 4% standard milk of milk sample） in each group were determined. The results showed that feed A and feed B were evaluated as excellent; feed C and feed D were good and feed E was general. The ratio of ammonia nitrogen in the feed A and the feed B was significantly lower than that in the feed C, the feed D and the feed E（P＜0.05）. The crude protein contents in the feed A and feed B were significantly higher than those in the feed C, the feed D and the feed E（P＜0.05）, and the crude protein content in feed C and feed D was significantly higher than that in the feed E（P＜0.05）. The content of neutral detergent fiber in the feed A and feed B was significantly lower than that in the feed D and the feed E（P＜0.05）, and there was no significant difference between the feed C and the other four feeds（P＞0.05）. The acid detergent fiber content in the feed A was significantly lower than that in the other four feeds（P＜0.05）, and there was no significant difference in the acid detergent fiber content in the other four feeds（P＞0.05）. There was no significant difference in crude ash and dry matter content among the five feeds（P＞0.05）. There was no significant difference in dry matter intake among the experimental groups（P＞0.05）. The milk yield in the groups Ⅰ, Ⅱ and Ⅲ was significantly higher than that in the groups Ⅳ and Ⅴ（P＜0.05）, and there was no significant difference among groups Ⅰ, Ⅱ and Ⅲ（P＞0.05）. The milk fat rate in the groups Ⅰ and Ⅱ was significantly higher than that in the groups Ⅳ and Ⅴ（P＜0.05）, and there was no significant difference between the group Ⅲ and the other four groups（P＞0.05）. There was no significant difference in milk protein rate, lactose rate, total solid and non fat solid content among the groups（P＞0.05）. The 4% standard milk content in experimental groupⅠ was significantly higher than that in experimental groups Ⅲ, Ⅳ and Ⅴ（P＜0.05）; experimental groups Ⅱ, Ⅲ was significantly higher than experimental groups Ⅳ and Ⅴ（P＜0.05）. The results indicated that the mixed silage of rice straw and corn straw with different addition ratios had no significant effect on the dry matter intake of Holstein cattle. When the fresh weight ratio of rice straw and corn straw was 0∶10 and 1∶9, the quality of mixed silage and milk production performance of Holstein cattle were higher.