OBJECTIVE： To establish the method for the content determination of related substance in Terazosin hydrochloride tablets. METHODS： HPLC and principal component self-control with correction factor were adopted. The determination was performed on Agilent Zorbax Eclipse XDB C18 column with mobile phase consisted of acetonitrile-perchloric acid solution （20 ∶ 80， V/V） at the flow rate of 1.0 mL/min. The detection wavelength was set at 246 nm， and sample size was 20 μL. The column temperature was 50 ℃. The linear equations of terazosin hydrochloride， impurity A， B， C were drawn. The correction factors of each impurity related to terazosin hydrochloride were calculated by slope， and relative retention time was used to determine the position of impurities. The contents of impurity A， B and C in 3 batches of Terazosin hydrochloride tablets were determined and compared with the results of impurity control method. RESULTS： The relative retention time of impurity A， B， C was 0.39， 0.74， 2.77， respectively； the linear range of them were 0.25-3.0 μg/mL， respectively. The correction factors were 0.75， 1.09， 0.84， respectively. The detection limits were 0.35， 0.51， 0.43 ng， and the limits of quantification were 0.70， 1.02， 0.86 ng， respectively. The contents of impurity A， B and C in 3 batches of Terazosin hydrochloride tablets were 0.11％-0.13％， 0.03％ and 0.09％-0.12％； impurity B did not detected. The results are consistent with the determination of impurity control method. CONCLUSIONS： The method is simple， rapid and accurate for the content determination of related substances A， B， C in Terazosin hydrochloride tablets.