Abstract: In order to define the carcass economic value of black Muscovy duck, the performance of slaughtering meat quality and the chest muscle nutrients of male and female black Muscovy duck aged at 70 days and 120 days were analyzed. The results showed that: ①Slaughter performance: live weight, carcass weight, carcass rate, eviscerated weight, half carcass weight, leg muscle of the drake aged 120 days were significantly higher than that of the drake aged 70 days, and the differences were significant (PP>0.05). So the drake aged 120 days and the female duck aged 70 days had good slaughter performances.②Meat quality: the differences of chest, leg muscle pH, and drip loss between the male and female black Muscovy duck aged 70 days were not significant (P>0.05). ③Chest muscle nutrients: the differences of moisture, dry matter, crude protein, crude fiber, and crude fat content in chest muscle between the black Muscovy duck aged 70 and 120 days were not significant (P>0.05). ④Amino acid content of chest muscle: the amino acid content in chest muscle of female duck aged 70 days, including threonine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine and the essential amino acids were higher than that of drake aged 70 days(P<0.05). The amino acid content in chest muscle of drake aged 120 days, including threonine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine and the essential amino acids were higher than that of drake aged 70 days (P <0.05). Compared the amino acid contents in 70 day-age ducks' chests, that of the female ducks was higher than that of the drakes; while, compared the amino acid contents in drakes’ chests, that of the 120 day-age drakes was higher than that of 70 day-age drakes.