Abstract: The nutrient intake of Gansu Alpine Fine-Wool ewes is often insufficient during late pregnancy. Therefore, three complementary concentrates (type Ⅰ, Ⅱ, and Ⅲ) with different energy and protein levels were designed and tested as supplementary feeds for Gansu Alpine Fine-Wool ewes during late pregnancy. Sixty healthy ewes with similar body weight in late pregnancy were randomly divided into four groups (A, B, C, and D). Each group comprised of 15 ewes with 1 ewe per replicate. Groups A, B, and C were fed with supplementary feed Ⅰ, Ⅱ, and Ⅲ, respectively, while group D was grazed on pasture according to the local practice. The experiment lasted for 68 days. The average daily weight gain of group A, B, C was 102, 109 and 114 g, respectively, and the lamb birth weight was 4.09, 3.91 and 4.40 kg, respectively. These values were higher than the corresponding values in group D. The serum glucose, triglyceride, and blood urea nitrogen concentration in ewes were significantly affected by supplementary feed Ⅲ (P<0.05). The total protein and aspartate transaminase contents were significantly affected by feed Ⅱ. The total nitrogen and rumen protein nitrogen contents in the rumen liquid of ewes were significantly higher in groups A, B, and C than in group D (P<0.05), and were significantly higher in group A than in groups B and C. The highest urea nitrogen content was in group B (P<0.05). The concentration and molar ratio of volatile fatty acids were significantly higher in groups A, B, and C than in group D (P<0.05), and the acetate/propionate ratio was significantly lower in groups A, B, and C than in group D (P<0.05). The rumen fluid pH and ammonia nitrogen concentration did not differ significantly among the four groups (P>0.05).