Objective To establish a UPLC method for simultaneous determination of 15 impurities in atorvastatin calcium active pharmaceutical ingredient(API). Methods Anal. was performed on Shimadzu Shim-pack Velox PFPP(2.1 mmx100 mm, 1.8 μm) column. Gradient elution was adopted, with 3.9 g/L ammonium acetate buffer(pH 5.0):acetonitrile: methanol:tetrahydrofuran(without stabilizer)=67:21:6:6 as mobile phase A, and 3.9 g/L ammonium acetate buffer(pH 5.0):acetonitrile: methanol:tetrahydrofuran(without stabilizer)=27:61:6:6 as mobile phase B. The flow rate was 0.43 mL/min, the detection wavelength was 244 nm, the column temperature was 35 °C and the sample room temperature was 10 °C, and the injection volume was 1.8 μl. Results Atorvastatin calcium and its impurities were well separated The linear ranges of 15 impurities were 0.3-3 μg/mL(r>0.999, n=6). The average recoveries of the impurities were 96.3 %, 99.1 %, 99.9 %, 102.4 %, 96.4 %, 99.8 %, 99.4 %, 104.9 %, 106.4 %, 105.4 %, 100.1 %, 98.9 %, 94.7 %, 94.4 %, 101.4 %, resp., and the parallelism between different concentrations was good. The repeatability, injection precision and intermediate precision of 15 impurities were all good, and the test solutions were stable within 48 h. The method showed good durability except high requirements for chromatog. column. Conclusion The method is simple, rapid, with good resolution and strong specificity, and can be used for the determination of related substances in atorvastatin calcium API.