Abstract: Chinese herbal medicine sample was digested with HNO3-HClO4-H2SO4 and reduced by thiourea and ascorbic acid,to transform As(Ⅴ) to As(Ⅲ).Arsenic was then determined by flow injection-hydride generation-atomic absorption spectroscopy (FI-HG-AAS) with KBH4 as reducing reagent and dilute HCl as carrying solution.Linear relationship between values of absorbance and mass concentration of arsenic was obtained in the range of 1.6-32.0 μg·L-1,with detection limit (3s/k) of 0.32 μg·L-1.Three samples of Chinese herbal medicines were analyzed by the proposed method,values of RSD′s (n=6) obtained were in the range of 5.1%-8.1%,and values of recovery found by standard addition method were in the range of 91.4%-106.1%.