Abstract:The tea polyphenol is one of the most important components for the quality of tea.Exogenous enzymes treatment can effectively change the tea polyphenols of tea which is of great significance for improving the quality of tea.In present work，six kinds of medium were selected for Aspergillus niger fermentation to produce extracellular enzymes and the extracellular enzymes were used to extract oolong tea. A method for the determination of catechins content of the oolong tea was developed by liquid chromatograph-mass spectrometry.The intra-and inter-day precision of the method by using the optimized chromatographic conditions were less than 3.72%and 5.72%respectively，and the intra-and inter-day accuracy were between 99.70%-104.16%and 96.17%-106.61%.The recoveries of standards ranged from 88.34%to 107.52%.And the results showed that he extracellular enzymes derived from pomelo peel and tea stalk medium increased the content of tea polyphenols. The extracellular enzymes derived from tea stalk medium made the content of non-galloylated catechins increase significantly.The extracellular enzymes derived from tea stalk medium increased the content of non-galloylated catechins.Sensory evaluation results showed that the extracellular enzymes derived from tea stalk medium made the oolong tea had lower bitter and astringent taste than the referenced oolong tea，but the sour taste was enhanced obviously；the extracellular enzymes derived from wheat bran medium made the oolong tea astringent taste enhanced significantly.