Abstract: Objective To establish the related substance method of rosuvastatin calcium tablets. Methods Prepared eight impurities of rosuvastatin calcium tablets first, Column: Agilent extend-C18(4.6 mm×250 mm, 5 μm) with mobile phase consisted of 0.05 M sodium dihydrogen phosphate buffer (adjusted to pH 2.0 with phosphoric acid): acetonitrile: methanol=46:20:34 at a flow rate of 0.7 mL·min-1 when the detective wavelength was set at 242 nm, used external standard method to calculate the content of impurities. Results The contents of (3S, 5S)-rosuvastatin calcium, 5-oxo-rosuvastatin and rosuvastatin-5S-lactone are more than others in three batches of rosuvastatin calcium tablets. Conclusion The contents of impurity A, B, C should not be more than 0.5% and impurity D, E, F, G, H should not exceed 0.2%, for each unspecified impurities not more than 0.2% and not more than 1.5% for total.