Abstract: In the present experiment, fifteen amino acids in the root and stem of Rhododendron Simsii Planch( dry sample) were measured with o- phthalic aldehyde- -mercaptoethanol precolum denivalization, reversed- phase gradient elution and fluoresence detection.There are 12. 74  amino acids in the root, and 5.30  of them are essential amino acids.There are 8.41 amino acids in the stem, and 3.52  of them are essential amino acids.The satisfactory separation was obtained by this analyt ical method. The mean recovery could reach 93.6%, the mean Vaniation coefficient of retention time of fif teen amino acids was 1.0 ± 0.4% ( mean ± S. D) , while that of peak area was 4.2±0.8% , in the range of 10 pmol to 2 nmol, the amounts were linearly related with the peak areas( r=0. 987±0. 009, mean ±S. D) .

Key words: Rhododendron Simsii Planch, HPLC, amino acid