Objective To investigate the corrosion behavior of 16Mn steel in sodium aluminate solution with different S2O32? concentrations. Methods The corrosion behavior of 16Mn steel was studied by salt spray corrosion, weight loss method, electrochemical corrosion test and analyzed by SEM, EDS. Results Corrosion rate was raised from 0.4990 g/(m2·d) to 0.5180 g/(m2·d) and the maximum pitting depth rose from 3.6 μm to 4.5 μm, when the concentration of S2O32? increased from 3 g/L to 7 g/L, while the corrosion current density rose from 0.648 μA/cm2 to 5.186 μA/cm2 and the radius of capacitive arc decreased gradually. According to EDS analysis, corrosion products were composed of four elements (O, Al, S, Fe), the contents of Al, O were higher than those of the other elements and decreased after increased first with increase of S2O32? concentration. Conclusion Existence of thiosulfate accelerated corrosion of 16Mn steel in sodium aluminate solution. Corrosion behavior of 16Mn steel was notably affected by the changing concentration of S2O32?. Corrosion rate showed a trend of escalation with the increase of S2O32? concentration. Corrosion rate increased slowly in 3 g/L S2O32? for matrix protected by Al(OH)3 coatings on the surface of sample. The oxidation coating was penetrated by S2O32? after the S2O32? concentration increased to 4 g/L, and the corrosion rate increased relatively fast. However, the corrosion rate increased slowly and tended to be stable after the concentration of S2O32? increased to 5 g/L.