Penaeus japonicus is an important marine shrimps resource in China. In order to evaluate the nutritional value, the contents of general nutritional compositions, amino acids and fatty acids in muscle were compared between wild and farmed P. japonicus. The contents of muscle moisture and crude protein, fat and ash in wild P. japonicus were 77.16%, 17.74%, 2.08% and 1.79％, and those in farmed P. japonicus were 78.02%, 17.26%, 2.04% and 1.63％, respectively. The essential amino acids (EAA) in wild and farmed P. japonicus were 23.25％ and 22.43％, respectively. The amino acid score of essential amino acids were higher than 100 except Leu and Trp, so the protein of P. japonicus has a well-balanced amino acid composition. Wild P. japonicus has more unsaturated fatty acids (64.05％) than farmed group (60.34％). Higher n-3 polyunsaturated fatty acids (PUFAs), eicosapentainoic acids (EPA, 20:5 n-3), docosahexaenoic acids (DHA, 22:6 n-3) contents and lower C16:0, C20:0, C18:1, C18:2, C18:3 levels were detected in the wild group. Values of n-6/n-3 in muscle of farmed and wild P. japonicus were 0.30 and 0.23 respectively, which were both significantly lower than the maximum value (4.0) recommended by UK Department of Health (HMSO, 1994), while Values of the PUFA/SFA ratio of two groups were 0.60 and 0.74 higher than the minimum value (0.45) recommended by HMSO. Thus the muscle of farmed and wild P. japonicus are both healthy and safe, and the the muscle of wild P. japonicus is more beneficial to human health.