Abstract: OBJECTIVE To estahlish a method for the simultaneous determination of alantolactone, isoalantolactone, dehydrocostuslactone and costunolide in Tibetan medicine Qiwei Tiexue pill by GC. METHODS Samples of Qiwei Tiexue pill were determined by HP-5 capillary column(30 m×0.32 mm, 0.25 μm). The column oven temperature was 140℃. FID was used as detector with a temperature of 250℃, and the inlet temperature was 220℃. The carries gas was nitrogen and the flow rate of carries gas was 1.0 mL·min^-1. The air flow rate was 450 mL·min^-1. The hydrogen flow rate was 45 mL·min^-1. The injection volume was 1 μL. Split ratio was 20:1. RESULTS The linear ranges of alantolactone, isoalantolactone, dehydrocostuslactone and costunolide were 7.120 2-71.202 2 μg·mL^-1(r=0.998 4); 5.478 5-54.785 1 μg·mL^-1(r=0.997 1); 8.195 3-98.344 1 μg·mL^-1 (r=0.996 7); 6.395 4-76.744 8 μg·mL^-1(r=0.997 2), with average recoveries(n=6) of 98.11%(RSD=1.04%), 98.12%(RSD=1.09%), 98.39%(RSD=1.26%), 97.52%(RSD=1.25%), respectively. CONCLUSION This method is effective and reliable, which can be used for quality control for the determination of Inula racemosa and Aucklandia lapp in Qiwei Tiexue pill.