In order to explain the effects and mechanisms of microorganisms on the fermentative process of Pu-erh tea, For the purpose of providing the theory and data support for industrialized fermentation of Pu-erh tea, the monoxenie fermentation under individual microorganism and mixed fermentation experiments of Pu-erh tea were carried out. The experiments discovered the effects of different microorganisms by tracing the influences of different strains to sense quality and physics and chemistry index in the fermentative process of Pu-erh tea. The results showed that in the fermentative process of Pu-erh tea, the color of tea became to hepatic from green, the bitter sense of tea soup taperred, the tea soup was red and bright. The contents of tea polyphenol and water extract were decreased, while the contents of theabrownin and caffeine were increased. Furthermore, the influence of fungi to these components was largest, yeast was less than fungi, bacteria was least. Mixed fermentation tea possessed ripe tea quality when fermented 20d. Forementioned results proved that fermenting Pu-erh tea with reasonable matching can not only shorten fermentative time, but also preferably control and benchmarking the fermentative trend and result of Pu-erh tea.