Abstract: The decontamination simulation tests were performed in dynamic decontamination loop to choose the suitable decontamination condition for fast reactor components with sodium. In the tests, 304SS and 316SS were used as sample which were exposed in sodium for 3 700 h at 530 ℃. A solution of 12.5 g/L of sulfuric acid and 30 g/L of phosphoric acid was chosen as one-step decontamination solution. The measurement and analysis for decontamination depth, micro morphology and mechanical property were performed after test. The decontamination depth of 304SS and 316SS can reach about 10 μm and 4 μm respectively, and increases with temperature, time and flow rate. With the characteristic of simple operation, fast decontamination rate and little waste solution, the sulfuricphosphoric acid is a high effective decontamination solution for fast reactor components with sodium.