OBJECTIVE： To study the effects of different extraction methods of decoction machine on the extraction rate of effective components in medicinal materials. METHODS： 3 kinds of TCM decoction pieces with clear component and different parts （rhizome Salvia miltiorrhiza， fruit Gardenia jasminoides and leaves Morus alba） were selected and decocted by 3 decoction methods （decocting for 25 min， decocting for 25 min after soaking for 30 min， decocting 50 min after soaking for 30 min）. The contents of effective components （salvianolic acid B， jasminoidin， rutin） were determined and decocting rates were calculated. RESULTS： Using 3 decoction methods， decocting rates of salvianolic acid B from S. miltiorrhiza were 41.9％， 71.6％， 62.1％； those of geniposide from G. jasminoides were 68.9％， 72.2％， 75.6％； those of rutin from M. alba were 36.4％， 47.2％， 56.2％， respectively. CONCLUSIONS： The decocting rates of geniposide and rutin are slightly increased with decoction time prolongs， while the decocting rate of salvianolic acid B is decreased with decoction time prolongs. It is suggested to adopt different decoction time for medicinal materials of different prescriptions， different parts and different effective components when using decoction machine.