Abstract: Effect of different process conditions on quality of pu-erh tea during pile-fermentation was studied by orthogonal test in laboratory-scale. Three conditions which included initial water content, initial pH and pile-turning interval were set up. The results showed that appropriate initial water content and pile-turning interval could be favorable in the quality of pu-erh tea and the transformation of a series of chemical constituents such as polyphenols, while the initial pH values had little effect on them. Combined with the sensory evaluation, the optimal pile-fermentation conditions were the 45% initial water content, none-adjustment initial water pH and pile-turning interval of 6 days.