Objective: To develop an accurate and rapid ultra-performance liquid chromatography (UPLC) coupled with a photodiode array (PDA) method for the simultaneous determination of artemisinin (Art), arteannuin B (Art B), arteannuin C (Art C), dihydroartemisinic acid (DHAA) and artemisinic acid (AA) in Artemisia annua L. Methodology: Chromatography separation was performed on an ACQUITY UPLC BEH C18 Column with isocratic elution; the mobile phase was 0.1% formic acid aqueous solution (A) and acetonitrile (B) (A:B = 40:60, v/v). Data were recorded at an ultraviolet (UV) wavelength of 191 nm for Art, Art C, DHAA and AA, and 206 nm for Art B. Results: The calibration curves of the five sesquiterpene components were all linear with correlation coefficients more than 0.9990. The linear ranges were 31.44–1572 μg/mL, 25.48–1274 μg/mL, 40.56–2028 μg/mL, 31.44–1572 μg/mL and 26.88–1396 μg/mL for Art, Art B, Art C, DHAA and AA, respectively. The precision ranged from 0.08% to 2.88%, the stability was from 0.96% to 1.66%, and the repeatability was all within 2.42% and had a mean extraction recovery of 96.5% to 100.6%. Conclusion: The established UPLC–PDA method would be valuable for improving the quantitative analysis of sesquiterpene components in Artemisia annua L.