OBJECTIVE： To establish the method for simultaneous determination of related substances in Amlodipine hydrochlorothiazide and valsartan tablets. METHODS： HPLC method was used. The determination was performed on Symmetry C18 column with mobile phase consisted of water-acetonitrile-trifluoroacetic acid （90 ∶ 10 ∶ 0.1，V/V/V） and water-acetonitrile-trifluoroacetic（10 ∶ 90 ∶ 0.1，V/V/V）（gradient elution） at the flow rate of 0.6 mL/min. The detection wavelength was set at 237 nm （impurity A） and 225 nm （impurity B， C， D）. The column temperature was 30 ℃. RESULTS： The linear range of impurity A， B， C， D were 93.43-987.34 ng/mL （r＝0.999 4），12.27-255.92 ng/mL（r＝0.999 6）， 78.96-657.17 ng/mL（r＝0.999 9）， 28.39-218.16 ng/mL（r＝0.999 7）， respectively. The limits of quantitation were 91.27， 11.35， 78.31， 26.56 ng； the limits of stability and detection were 22.98， 3.13， 19.17， 8.16 ng. RSDs of precision tests were lower than 2.0％. Only impurity A was found in repeatability test，RSD＝0.79％. Recoveries were 99.4％-100.6％（RSD＝0.41％，n＝9），98.9％-102.0％（RSD＝1.04％，n＝9），99.4％-100.9％（RSD＝0.56％，n＝9）， 98.6％-101.2％（RSD＝0.92％，n＝9）， respectively. CONCLUSIONS： The method is simple， rapid， sensitive and repeatable， and can be used for the determination of related substance in Amlodipine hydrochlorothiazide and valsartan tablets.