Abstract： Objective To establish an HPLC method to determine the related substances in vonoprazan fumarate injection.Methods YMC-Pack Pro C18 column(4.6 mm× 150 mm,3 μm)was used.Mobile phase A was 0.04 mol·L-1 potassium dihydrogen phosphate solution(containing 0.2％triethylamine,adjusted to pH 6.6 with phosphoric acid)-acetonitrile-isopropanol(92∶4∶4),while mobile phase B was 0.04 mol·L-1 potassium dihydrogen phosphate solution(containing 0.2％triethylamine,adjusted to pH 6.6 with phosphoric acid)-acetonitrile(40∶60).Gradient elution was used,the flow rate was 1.0 mL·min-1,the column temperature was 40 ℃,the detection wavelength was 220 nm,and the injection volume was 20 μL.Results Impurity H,impurity B,impurity C,impurity F,impurity D,impurity E,impurity J and vonoprazan all showed good linear relationship with the peak area at the concentration ranges of 0.12～4.99,0.12～4.99,0.12～4.90,0.13～5.01,0.12～4.99,0.13～5.01,0.13～5.01 and 0.13～5.01 μg·mL-1(r＞0.9990).The average recoveries of the above 7 impurities ranged 94.72％～100.67％,with all the RSD less than 2.0％.The quantitation limits of 7 impurities and vonoprazan were 0.12～0.13 μ·g·mL-1 and the detection limits were 0.040～0.043 μg·mL-1.Conclusion The method is exclusive,sensitive and accurate,which can be used to determine the related substances in vonoprazan fumarate injection.