Abstract: Simulating the process of Patinopecten yessoensis depuration under laboratory condition,the changes of total count of bacteria colonies,coli forms level,microbial ecology,whiteness and nutrition components was detected with the extension of depuration time. The results indicated that 17 kinds of different genera of bacteria were identified before the depuration process and gram negative bacteria accounted for obvious advantages,after the depuration process,9 kinds of different genera of bacteria were identified,and Pseudomonas,Enterobacteriaceae,Planococcus,Halococcus,Shewanella,Flavobacterium,Escherichia,Sporolactobacillus in the late of depurating were not checked out.Total bacterial count and coliform bacteria with depuration extending were gradually decreased. The Whiteness and water content were increased with extension of depuration,while the glycogen and crude fat with the extension of depuration time were gradually decreased. The content of crude protein were increased in a small amount during the depuration process.Through the sterile seawater depuration,the bacteria phase of Patinopecten yessoensis tended to be simpler and nutritional quality got worse.