In order to evaluate the muscle nutritive composition in Mount Changbai boar, the contents of intramuscular fat and fatty acids were measured by methanol extraction and gas chromatography and compared between high body weight boar（100±5）kg and low body weight boar（80±5）kg. The results showed that the intramuscular fat contents of high body weight boar were significantly higher than that of low body weight boar（P＜0.05）, but the free water contents of high body weight boar were significantly lower（P＜0.05）. In the high body weight boars, the relative contents of myristic acid and palmitic acid were very significantly lower（P＜0.01）, but the linoleic acid, the ratio of polyunsaturated fatty acid and saturated fatty acid were very significantly higher（P＜0.01）. In the fresh pork, the contents of palmitoleic acid, linoleic acid, unsaturated fatty acid and the ratio of polyunsaturated fatty acid and saturated fatty acid were very significantly higher than that of the low body weight boar（P＜0.01）, and the contents of monounsaturated fatty acid, the ratio of unsaturated fatty acid and saturated fatty acid were significantly higher than that of the low body weight boar（P＜0.05）. In conclusion, the slaughter weight of Mount Changbai boar had significant effect on the contents of muscle fatty acids.