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In China, Artemisia annua L. has been used as a traditional medicine for nearly a hundred years. In 1972, artemisinin, an antimalaria monomer, has been extracted from A. annua by China Cooperative Research Group. Since then, an extensive research on A. annua has been spread out among the scholars in domestic and overseas. Pharmacological studies showed that A annua has various abilities of bioactivity such as anti-stomatocace, anti-pregnant, anti-fibrosis, antitumour, protecting skin, antiphlogistic and so on. A. annua synthesizes and accumulates a variety of secondary metabolites. It had substantiate that some of the secondary metabolites had insecticidal, antifungal and allelopathic activities.In this paper, we studied the acaricidal activities of extracts from A. annua, determined the distribution of acaricidal components in different parts of this plant by the different resolves, and then carried out further studies on isolation of acaricidal substances. The main results are as follows:1.1 Extracting from Artemisia annuaThe extracts of Artemisia annua would be extracted simultaneously, or sequentially, from the five solvents. After comparing the four ways of extraction: soaking extraction under room temperature, constant temperature extraction, whisking and Soxhlet’ extractions, the datum showed that Soxhlet was the most efficient way.The parallel extract of leaves in July with water was the highest yield ratio in the all parallel extracts. Extract ratio of soaking extraction under room temperature was 20.660%, and Soxhlet’s was 22.693%. The parallel extract with acetone is the lowest about extract ratio, extract rate of soaking extraction under room temperature was just 6.987%, Soxhlet’s extraction was 8.710%. The different parts of Artemisia annua could be arranged in the following order of yield ratio: leaves in July > stems in July > aerial parts in April.1.2 Bioassay of extractions from Artemisia annua against Tetranychus
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