Abstract: HG-AFS was applied to the analysis of 5 kinds of Chinese medicinal herbs grown in Hainan province,namely Semen Arecae,Fructus Alpiniae Oxyphyllae,Fructus Amomi,Radix Moindae Officinalis and Lignum Aquilariae Resinatum,for the contents of mercury and arsenic.Details of pretreatment and digestion of sample as well as the working conditions of instrument were described.Influential factors,including the concentration and kinds of acid used in sample digestion,concentration of potassium borohydride used,reduction of pentavalent arsenic and interferences of co-existing metal ion,were studied and optimized.Detection limits of this method for mercury and arsenic were found to be 1.5 ng·g-1 and 7.0 ng·g-1 respectively.Recovery tests were made on the base of 5 substantial medicinal herbs,giving results in the ranges of 90%-93% for Hg and 90%-91% for As.