Abstract: The degradation of protein in processing of Yiluxian were investigated in this paper.Several aspects,such as TN,Non- protein nitrogen,protein components,free amino acids and TVBN,were particularly detected from samples got from 5 different time points.Results showed there was no significant variation of TN content( p > 0.05)and the content of non- protein nitrogen were increased by 54.44%.In further analysis by SDS- PAGE,myofibrillar proteins degraded as well as occurred aggregation while sarcoplasmic proteins degraded,individually.Free amino acids had a fluctuation in 36 h( decline) and 72 h( rise) in marinated and in 24 h( decline) and 48 h( rise) in desalination process. Eventually,free amino acids were increased by 53.5%. TVBN had an upward trend in the whole process and a weak decline was observed in 24 h after desalination.The total value of TVBN,finally,reached16.15 mg /100 g which was in line with national standards.