The speciation analytical method was developed to detect the arsenic (As) and research its styles, contents and distribution in Acori tatarinowii. The arsenic speciation was separated by high performance liquid chromatograph with anion exchange column (HAMILTON PR-X100, 4.1 mm×250 mm，10 μm). Mobile phases were ultra-pure water (A) and 50 mmol/L ammonium carbonate with 1% methanol（pH 8.5, B）. Inductively coupled plasma emission and mass spectrometry was involved to detect arsenic speciation. The linear ranges were between 0.995 and 0.999, and the rate of recovery ranged from 89% to 97%. The method was confirmed to be accurate, stable and reliable. The results showed that leaves soaked in different contents As (III) solution for different times, only inorganic speciation of As was found, among which As (III) was the main speciation. The rhizome of A. tatarinowii was the main enrichment position absorbing the inorganic arsenic. Both the rhizome and the leaves could transform the As (III) to As (V).