An UV-quantitative analysis method for the theabrownin (TB) in Pu-erh tea and its derived products was established in the present study. The results showed that the Pu-erh tea shows characteristic absorption at the wavelength of 270 nm, which can be used as wavelength for the content determination of TB. The preparation methods of standard TB and standard curve were also established. The determination results show that the method is simple, the results have certain credibility, and the established method can be used for the determination of TB in Pu-erh tea and its derived products.