To discuss formation mechanism of biogenic amines in fish during pickling and drying preliminarily,dynamic change and the mutual relationship of salinity,moisture content,Aw,pH,protein hydrolysis index (P.I.),Non-protein nitrogen (NPN),free amino acid,microorganism,biogenic amines and relevant biogenic amine indices in hairtail (Trichiurus lepturus) during pickled and dried processing were studied.The results showed that,the pH in curing phase increases but fell in a dry stage.Salinity,P.I.,total plate counts,lactic acid bacteria,micrococcus and staphylococcus contents increased generally during process stage but moisture content and Aw continued to decline.There has been a marked protein degradation reaction,the content of NPN and free amino acids considerably increase,the total biogenic amine content increased 2.26 times,which cadaverine content significantly increased by 157 times,followed by histamine during whole process stage.Free amino acid and biogenic amines was significantly positive correlation,as the biogenic amine precursor to influence on the formation of biogenic amines,the microbes have played an important role in promoting and inhibition of biogenic amines,the formation of biogenic amines are affected by factors such as pH,salinity,Aw,mutual influence,is an extremely complex process in hairtail pickling and drying process.