A method for extracting stilbene compounds comprises the following steps: grinding a medicinal material rich in stilbene compounds such as rheum officinale extracting the medicinal material with a herbal flash extractor for one to four times, 5-20 minutes each time filtering and combining filtrate and concentrating the filtrate to dryness the proportion of the medicinal material to a solvent being 1 g: 10 ml-1 g:15 ml.
