The regulation of structure and composition is very important for obtaining stainless steel with good comprehensive properties. In present paper, Fe2O3 powers with different excess ratios were added in reaction powders to make aluminothermic reaction completely and reduce the content of Al in the 316L ASSs. The effects of excess Fe2O3 in reactions on microstructure and tensile properties of micro-nano structure of 316L austenitic stainless steels were analyzed in detail. The results showed that, with the increase of Fe2O3 excess percentage, the volume fraction of ferrite phase reduced significantly while the volume fraction of nanocrystalline increased from 87.4 % to 93.4 % and the average grain size decreased from 32 nm to 22 nm. The comparative analysis showed that the Fe2O3 excess percentage of 5.0 % was the best process parameter for the 316L ASSs preparation by the aluminothermic method. For the single phase austenitic steel prepared under this condition, the tensile strength was 573.92 MPa, the yield strength was 340.12 MPa, and the elongation was about 4.68 %.