Abstract: OBJECTIVE To establish an HPLC method for determining the contents of the related substances of cetilistat. METHODS The condition of detection were as follows:Agilent Phenyl column (250 mm×4.6 mm, 5 μm), the gradient mobile phase consisted of 5 mmol·L^-1 potassium dihydrogen phosphate (adjust with 10% phosphoric acid to pH 4.0) and acetonitrile with a flow rate of 1.0 mL·min^-1, the UV detection wavelength was 226 nm. RESULTS The resolution of cetilistat and relate substances was good. The calibration curves were linear in the range of 0.049 5-1.981 0 μg·mL^-1 for impurity A (r=0.999 9); the calibration curves were linear in the range of 0.059 9-0.399 1 μg·mL^-1 for impurity B (r=0.999 9); the calibration curves were linear in the range of 0.059 6-0.397 5 μg·mL^-1 for impurity C (r=0.999 9). The average recoveries of impurity A, impurity B and impurity C were 104.2%, 107.0% and 107.8% respectively; the RSDs were 2.09%, 1.77% and 2.18%, respectively. CONCLUSION The method is simple, accurate, reliable and can be used for the quality control of the related substances of cetilistat.