A HPLC method for determination of related substances in trityl losartan was established. Lichrospher RP-select B 60A column (250 mm×4.0 mm, 5 μm) was used, the gradient mobile phase consisting of 0.01 mol·L-1 sodium dihydrogen phosphate (pH=2.5)-acetonitrile with a flow rate of 1.5 mL·min-1 was used. The column temperature was kept at 35°C and the detection wavelength was set at 230 nm. Trityl losartan and related substances could be well isolated. The method is simple, rapid, accurate and suitable for determining the related substances in trityl losartan.