The inorganic arsenic(iAs) in seaweed food is an important safety index in seafood quality detection. High performance liquid chromatographyhydride generationatomic fluorescence spectrometry(HPLC-HG-AFS) was used to determine the iAs in seaweed food. The concentration of extraction reagents, the extraction time and instrument conditions were optimized. A new method to determine the content of inorganic arsenic in seaweed food using HPLC-HG-AFS was obtained: firstly the seaweeds were extracted with 1.2 mol/L HCl at 70 ℃ for 1 h , then the extracts were oxidized with hydrogen peroxide, and finally were analyzed by HPLCHGAFS under the condition of 15 mmol/L(NH₄)₂HPO₄ flow phase(pH=6.0). The average recovery rates of 0.10 mg/kg and 1.00 mg/kg AsⅢ in samples were all above 92% and the relative standard deviations were all below 4% with a high accuracy. The present study proved that HPLC-HG-AFS was a reliable method to determine the iAs in seaweed food and provide enough evidences for the establishment of the standard for iAs in seaweed food.