Abstract: Triptolide was extracted from Tripterygium wilfordii Hook.f by pressurized liquid extraction with 1，2-dichloroethane. Main factors affecting the extraction process were discussed，and the optimum extraction conditions were obtained as：the solid to liquid ratio is 1:9.7，the extraction temperature is 115 ℃ and the extraction time is 80 min. Under the optimized conditions，the actual yield and purity of triptolide were 0.173‰ and 1.21％ respectively. This process has obvious advantages as compared with conventional reflux extraction.