The experiment was conducted to study the effects of mix-ensiling of different ratios of withered Alhagi sparsifolia to cottonseed hulls on silage quality. Seven treatments (treatment Ⅰ～Ⅶ) contained withered Alhagi sparsifolia, cottonseed hulls and the different ratio mixture of them (3∶7, 4∶6, 5∶5, 6∶4 and 7∶3), respectively, for silage fermentation, with 3 replicates for each treatment. Silages samples were evaluated for sensory indices and analyzed for pH, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), acetic acid (AA), propionic acid (PA), butyric acid (BA), lactic acid (LA) and total acid (TA). The results showed as follows: Alhagi sparsifolia could be ensiled successfully although it was legumes herbage, and the primary fermentation was homolactic fermentation. The contents of water soluble carbohydrate (WSC) in treatments Ⅴ, Ⅵ and Ⅶ were significantly higher than that in treatment Ⅱ (P＜0.05), the pH and ratio of NH3-N/TN in treatments Ⅳ, Ⅴ, Ⅵ and Ⅶ were significantly lower than those in treatment Ⅱ （P＜0.05, P＜0.01）, and the contents of TA in treatments Ⅳ, Ⅴ, Ⅵ and Ⅶ were significantly higher than that in treatment Ⅱ (P＜0.01）, the contents of lactic acid (LA) in all mix-ensiling were significantly higher than that in treatment Ⅱ (P＜0.01）. It was concluded that Alhagi sparsifolia and cottonseed hulls mix-ensiling could improve the quality of cottonseed hulls silage.［Chinese Journal of Animal Nutrition, 2010，22（4）:1107-1112］