Austenitic stainless steel utilized on a vehicle of mass rapid transit have composition 18 wt.% Cr-8 wt.% Ni. This steel is known to have a good corrosion resistance. Because of various pollutants, this material is prone to become less resistant to corrosion. Heat treatment is one of many methods to remedy the corrosion resistance. The material was subjected to heat treatment at 1030 °C for 5 h and 3 h and the other was cooling with various types of cooling, such as quenching. X-ray diffraction was used to characterize the structure because heat treatment modified the structure of these samples; the concentration of iron-alpha increases proportionally to the decrease in corrosion rate. To investigate the electrochemical behavior of these materials, potentiodynamic curves were obtained during the standard corrosion tests before and after heat treatment. The results showed that the full annealing method with rapid quenching is the best method for improving the corrosion-resistance of the austenitic stainless steel, compared to the annealing method with slow cooling.