Abstract: The nitrogenous compounds in mantle cavity fluid of Ruditapes philippinarum during live storage were investigated. The raw materials were divided into four groups, including control, ambient wet storage, ambient dry storage and chilled dry storage. The results indicated that, proximate composition of mantle cavity fluid were moisture 95%, ash 69.41% (dry basis), protein 15.82% (dry basis), total carbohydrates15.11% (dry basis), non-protein nitrogen (NPN) dominated total nitrogen accounting for 70% of the total. The total nitrogen, NPN, FAA, and carbohydratesin all three treatments increased to some extent compared with the control group. In general, the content increase of dry storage was higher than that of the wet storage, and the chilled was higher the ambient. The results of FAA indicated that the tastyamino acids comprising glutamic acid, glycine, alanine accounting for 50% or more of the total FAA in each group although there were significant differences between every amino acid. The 7 essential amino acids including threonine, valine, methionine, isoleucine, leucine, phenylalanine and lysine were detected, of which lysine was the highest. Analysis of amino acids composition of protein nitrogen showed that, essential amino comprising threonine, valine, methionine, isoleucine, leucine, phenylalanine and lysine accounting for 25%~37% of the total. In a word, live storage affected the nitrogenous compounds in mantle cavity fluid of Ruditapes philippinarum, and chilled dry storage affected the most. Mantle cavity fluid of Ruditapes philippinarum was rich in protein, carbohydrates, tasty amino acids and essential amino acid, which provided reference for developing nutritive seafood seasoning.