Abstract: Extraction of essential oil from the whole plant, leaves and stem of Sedum clavatum was implemented by microwave assisted hydro-distillation, and analysis were made on their component by gas chromatography-mass spectrometry. The optimal technology for extraction was experimented with single factor and orthogonal design. The result demonstrated that the extraction rate of essential oil from stem was about 4 times higher than that from leaf, and there were 2 same substances in essential oil from stem and the whole plant. The experiment showed the optimal technology for extraction of essential oil from different part of S. clavatum was as follows: solid-liquid ratio of 1:8, soaking time of 60 min, microwave power of 400 W, and extraction time of 3 h, the highest extraction rate reached 0.96%.