Abstract: 【Objective】 To compare the meat quality and characteristics of Bayinbuluk sheep of different months old under natural grazing conditions. 【Methods】 Six 6-month and 9-month-old male lambs under natural grazing conditions were randomly selected for slaughter, and the pH, chromaticity, cooking loss, shear force, conventional nutrients, amino acids and fatty acids contents of the longest dorsal muscle were determined and analyzed. 【Results】 The meat brightness (L^*), redness (a^*), yellowness (b^* values) and shear force values at 9-month-old were extremely significantly higher than those at 6-month-old (P<0.01), and the pH and cooking loss had no significant differences; The meat composition of protein, fat, and water had no significant differences between 6-months-old and 9 -months-old (P>0.05), the essential, nonessential and total amino acids content were extremely significant higher at 6-months-old than at 9-months-old (P<0.01), and the polyunsaturated fatty acid content was significant higher at 9-months-old than at 6-month-old (P<0.01). 【Conclusion】 There is a big difference in meat quality and nutrient composition between Bayinbruk lambs of different months old, the meat from 6-months-old lambs is of good tenderness, and that from 9-months-old lamb has the perfect lustrousness and good nutritional value. The quality and nutrition of different months at 6 months is of good quality and high tenderness; that at 9 months has bright luster and high nutritional value.