Abstract: The catechins composition of tea polyphenols with different origin areas and purities was investigated by HPLC, and the effect of silica gel column chromatography on the isolation of Epigallocatechin gallate（EGCG) from different tea polyphenols was compared. This experiment indicated that the mass of catechins in tea polyphenols did not increase with increasing purity of tea polyphenols. It was related to the origin area and techniques of tea polyphenols extraction. The right tea polyphenols must be chosen for the isolation of different catechins.