Inorganic arsenic is one of the main safe sanitation indexes in the quality inspection of aquatic products. So far, no standard methods of determining inorganic arsenic in aquatic products have been listed in ISO and CAC standards. Among all kinds of arsenides, inorganic arsenic is more toxic than numerous organic arsenic. So it is relatively proper to evaluate the food quality with the limited level of inorganic arsenic in food. Arsenic in food is likely to exist in different chemical forms, such as inorganic arsenic and organic arsenic. Inorganic arsenic was extracted in the chloride form by way of water bath with 6 mol/L HCl, implementing the separation of inorganic arsenic and organic arsenic. Then inorganic arsenic was determined under the condition of 2 mol/L HCl.