Abstract: The contents of hydrolytic amino acid and free amino acid of dandelion during the fermentation process were determined by automatic amino acid analyzer.Dandelion contains 18 kinds of amino acids,the percentage of human essential amino acid content of the total amino acid in each period of fermentation is up to 42%.The results showed that dandelion is a kind of high nutrient plant.Among human essential amino acids,the contents of Met and Cys are insufficient,which affect their nutritional value respectively. Finally,the flavor of dandelion was studied by the each flavor class amino acid in the free amino acid.Results showed that the content of bitter amino acids( Leu,Val,Arg,Ile,Trp,Met) was higher than others in the early fermentation process.In the main fermentation stage the contents of sweet amino acids( Ser,Thr,Gly,Ala,His,Pro) and umami amino acids( Glu,Asp,Lys) increased and were higher than the bitter in the late stage. Throughout the fermentation process,the content of aromatic amino acids( Tyr,Cys,Phe) changed a little.Dandelion's taste quality of 7~20d was the best.