Abstract: In this study,root,stem,leaf and flower of penony were used to extract polyphenol with ethanol.The 0.1 mol/L aluminium chloride amount and pH value for precipitating polyphenol in ethanol solution were explored,and the dissolution conditions of the polyphenol precipitate were optimized by using orthogonal test.The contents of polyphenol in root,stem,leaf and flower of penony were determined.Results showed that precipitation conditions of polyphenol in ethanol solution are as follows:0.1 mol/L aluminium chloride amount 2.5 ml and pH 5.3,and the dissolution conditions of the polyphenol precipitate are as follows:sulfuric acid concentration 1 mol/L,ratio of polyphenol precipitate to sulfuric acid(V/V),temperature 55 ℃ and time 5 min.The polyphenol content decreases from root,leaf,stem to flower.

Key words: peony, polyphenol, extraction technology, orthogonal test