Abstract: Using fresh and dry Lei bamboo leaves as the materials of the aromatic extract oil by the ethanol extraction and  dealing with by ultrasonic,distillation，and refining,clear light yellow transparent liquid of aromatic oil was obtained.By means of subtractive spectroscopy and spectrum fitting of FT-IR,the composition and groups of the two kinds of aromatic oil are determined and authenticated.It is found that in dry leaves there are more components than in fresh leaves,which provides strong support  for the principle and effects of selecting and using dry bambso leaves in traditional Chinese medicine.

Key words: Lei bamboo leaves；extraction；aromatic oil；spectrum-fitting, subtractive-spectroscopy