As a series of investigation on the ex-N compounds, the amino acid composition of the naturally grown and cultured prawn meat extracts was analyzed according to the following extraction conditions: 70% ethyl alcohol extraction, alcohol treatment of the same concentration after hot water extraction for 30 min, and 5% TCA treatment. The Protein content and the level of pure protein was 22 .8% and 18.4% in naturally grown prawn muscle, and 21.8% and 15.3% in the cultured prawn muscle, respectively. None protein nitrogenous compounds of the extracts were 4.4% in the naturally grown prawn muscle and 6.5% in the cultured prawn muscle, respectively. According to the different extract condition, ex-N compounds and the amino acid composition and related compounds and the amino acid composition and related compounds showed high level from 5% trichloroacetic acid extraction. The content of ex-N compounds of the cultured prawn muscle was 1033.0mg%. whereas the content of amino acids and related compounds-N was 825.3mg%, nearly reached to 80% to the total extractive nitrogen. A common feature of the free amino acid composition in the extracts of the muscles of the naturally grown and cultured prawn was high contents of glycine, proline, taurine, alanine and hydroxyproline.