Abstract:A Saccharomycetes strain was isolated from a ripe Pu-er tea samples.The sterilized Pu-er raw tea was fermented with this isolate.The important flavor chemical ingredients[amino acids，tea polyphenols（TP），caffeine，flavonoid（FL），total catechins（TC）and tea pigments]from tea samples were determinated and analyzed.The results showed that the contents of tea polyphenols（TP），total catechins（TC），theaflavins（TF）from the fermented tea samples increased，but the contents of amino acids，caffeine，flavonoid（FL），thearubigins（TR），theabromine（TB）from tea samples decreased during fermentation process.These results were different from the results of piles-fermented Pu-er tea.Therefore，Saccharomycetes strain affected evidently the quality of Pu-er tea.