Abstract: The homogenized sample (1.000 0 g) was added into 48 mL of 0.5 mmol·L^-1 ammonium carbonate solution-methanol (99+1) solution (pH 7.8). The mixture was mixed well by vortexing, and then ultrasonically extracted for 40 min. After 2 mL of 3% (φ) acetic acid solution was added, the mixture was allowed to stand at 4℃ for 5 min, and then centrifuged at 8 000 r·min^-1 for 10 min at 4℃. The supernatant was filtrated with a 0.45 μm filter, and 2 mL of the filtrate was taken and separated on a Hamilton PRP-X100 anion analytical column (250 mm×4 mm, 10 μm), with 0.5 mmol·L^-1 ammonium carbonate solution-methanol (99+1) solution (pH 7.8) and 20 mmol·L^-1 diammonium hydrogen phosphate solution (pH 8.5) as mobile phase for gradient elution. Trivalent arsenicAs (Ⅲ), pentavalent arsenicAs (Ⅴ), arsenic betaine (AsB), monomethyl arsenic (MMA) and dimethyl arsenic (DMA) in the eluate were determined by inductively coupled plasma mass spectrometry. The same linearity range of five kinds of arsenic species was within 100 μg·L^-1, and the detection limits (3S/N) were in the range of 0.2-0.6 μg·L^-1. Values of recovery obtained by standard addition method were in the range of 89.6%-102%, and RSDs (n=6) were in the range of 0.11%-3.8%.