In this paper the changes of Total Soluble Nitrogen (TSN) in 5%TCA extracts，Falin Phenol Positive Suhstnce，Free Amino Nitrogen (FAAN)，pH value and VolatilB Basic Nitrogen (VEN) ware studied for the quality ofoyster (Ostrea pZicateZa) stored under different temperatures. Moreover,the pepti-des in hot water extract were separated, and the molecular weights of them weremeasured The experimental results showed thet TSN values in 5%TCA solutionand Fnlin-Phenol positive substance increased initially，then decreased afterwards.The relative nontent of peptides with molecular weit ranging from 1000-3000MW increased as the storage period at 0℃ or 30℃ was prolonged. The pH value de-seended whereas the Y.BN content ascended with the prolongation of the storagetime. By using Arrhenius plat's principle, the change of VEN content was furtherstudied, showing that there was an inflection point an the plot at the temperatureof 22℃ .