Abstract: Silage can be affected by a variety of factors during fermentation, which reduce its feed and fattening qualities. We selected and combined silage microbial additives to address the problems that occur during the natural fermentation of silage maize, such as nutrient loss and mold. The performance of a compound of one strain of lactic acid bacteria (Lactobacillus acidophilus) and one strain of yeast (Saccharomyces cerevisiae), which were isolated from mixed silage maize collected in multiple spots in the central arid area of Ningxia Hui Autonomous Region, China, were tested. The compound lactic acid bacteria-yeast strain microbial additive was inoculated into silage maize; at the same time, silage without and with commercial microbial additives were set as the control group. The nutritional composition was determined after a 45-d fermentation period. The results indicated that the neutral detergent fibers (NDF) and acid detergent fibers (ADF) of the feed decreased significantly after treatment with compound microbial additives, while the dry matter content and ether extract (EE) increased significantly. The degradation of crude protein (CP) was slightly inhibited, although this was not significantly different to the control. The 75-d fattening study and 5-d digestive and metabolic experiments for Tan sheep showed that the average daily feed intake significantly increased, while the difference in the average daily grain, final weight and ratio of feed to gain were not statistically significant. During the course of fattening, the final body weight, average daily gain, and feed efficiency increased. Then, the digestive and metabolic experiments for Tan sheep were showing that the apparent digestibility for CP and EE were significant increased. NDF tends to increased, while the different in the apparent digestibility of ADF was statistically insignificant. Thus, it is clear that the compound microbial additives noticeably improved the feed quality of silage and that silage maize inoculated with compound microbial additives facilitated the growth performance of Tan sheep.