Objective: To develop an HPLC method for the determination of the impurity A in tirofiban hydrochloride injection.Methods: The anal. was conducted on an octadecyl bonded silica column [YMC-Triart C18 (4.6 mm × 250 mm, 5μm)] with the isocratic elution of 0.01 mol/L potassium dihydrogen phosphate buffer and acetonitrile (70:30) at the flow rate of 1.0 mL/min for 40 min.The temperature was 35°C, the detection wavelength was 227 nm and the injection volume was 50μL.Results: The principal components of tirofiban hydrochloride injection were well separated from the know impurities and the degraded produced by forced degradationThe test solutions with impurity A were stable within 12 h.The calibration curves of impurity A were linear in the self-concentration range of 0.013-0.082μg/mL, with the correction factors of 0.93.The average recovery (n = 7) was 98.7%, and the RSD (n = 7) was 1.7%.The RSDs (n = 9) of repeatability (n = 9) and the intermediate precision (n = 12) for impurity A were 3.7%, 0.5% and 1.2%, 3.4%, resp.The results showed that every impurity of A was less than identification limit of 0.2%, and the total impurity level was no more than 0.3% in the three batches of tirofiban hydrochloride injection.Conclusion: The established method is suitable for the determination of the related substances in tirofiban hydrochloride injection.