Abstract: To alleviate the single limitation of the natural rubber source in production,we initiated our studies by determining the potential alternative ability of Cynanchum chinense  R.Br which come from Mongolian plateau.The rubber was extracted from the aerial parts of plant with organic solvent,and the chemical constituents were qualitatived by Pyrolysis gas chromatography-mass spectrometry.Thirty-eight compounds were obtained from Cynanchum chinense and elucidated as rubber,linoleic acid ethyl ester,twenty-eight alkanes,forty-four alkanes,lupeol,and so on.The rubber was further quantified by Bromide solution method,and the result showed a higher rubber content in the aerial parts of Cynanchum chinense with average 11.73%.

Key words: cynanchum chinense R.Br, natural rubber, organic solvent extraction, polyisoprene