[en] The stable iodine prophylaxis plays an important role in public health response after nuclear power plants accident. According to the recent guidelines of the international organizations and other countries, the intervention level of stable iodine prevention, timing of taking medication, doses for different groups, and the contradictions were discussed in this paper. The chemical form and the formulation of the stable iodine were introduced, and something needs attention during stockpiling and distribution of the iodine. There were still some problems in China on the preparedness for the stable iodine prophylaxis after nuclear power plant accident, including the single type of potassium iodide tablet, short shelf life and no practical guidance. The preparedness of stable iodine should be strengthened. (authors)