Abstract: The effect of varying concentrations of nitric acid on the electrochemical corrosion of 304 austenitic stainless steel has been investigated. The study was carried out using potentiodynamic cyclic polarization, open-circuit potential measurements. The reaction process of 304 austenitic stainless steel in nitric acid was under discussion. 304 austenitic stainless steel shows the same electrochemical characteristics with other stainless steel, and its polarization curve contains several passive regions and active regions. Electrochemical measurements indicate that nitric acid improves the pitting corrosion resistance capacity of 304 austenitic stainless steel by promoting the formation of passive film on the surface, and shifts the open-circuit potential to more positive values. Furthermore, nitric acid effects the corrosion rates of stainless steel in two contradictory ways. The result shows that 0.5 mol/L nitric acid has the highest corrosion rate.