A method was proposed for the determination of trace cadmium in Chinese medicine herb Thymus serpyllum L.by graphite furnace atomic absorption spectrometry(GFAAS).A chemical modifier and its proper concentration,the influence factors including ashing and atomization temperatures,atomization time and coexisting ions were investigated.Under the optimum experimental conditions,the detection limit and the relative standard deviation of the method were 06 pg and 22%(n=11),respectively.The recovery was between 965% and 106%.The method is simple,rapid and accurate.A real sample Thymus serpyllum L.and a biological standard sample(GBW 08501)of Peach Leaves were analyzed for cadmium by this method to afford Satisfactory results.