In this paper, isolation and purification of tea polyphenols from tea dust, waste tea branches and leaves were systematically studied. Firstly, several key factors in water extraction of tea polyphenols was investigated and the most suitable ratio of tea leaves to water (g/ml), extraction temperature and extraction times were 1: 25, 95℃, 3 times (each time for 30min), respectively. Then, various precipitators were tried to purify the achieved crude tea polyphenols and ZnSO4 was shown to be the best one. Using Zn2+ as precipitator, the optimal precipitator additive dosage and pH value (regulated with NH4HCO3) were 5~6% and 6.4-6.8, respectively. Furthermore, the purified tea polyphenols was dissolved in sulfuric acid and extracted with ethyl acetate. The collected solution was evaporated and dried to give the final product. The total extraction ratio of tea polyphenols was above 13％.