In this article, we reveal that the optimal annealing temperature for DSS 2205 differs between acidic and neutral NaCl environments, rendering the limitation of utilizing pitting resistance equivalent number (PREN) to optimize annealing temperature. Elevating the annealing temperature leads to a better corrosion resistance of ferrite phase in the activation zone through Ni redistribution. In acidic NaCl systems, the optimal annealing temperature for DSS 2205 is co-governed by the Ni content and PREN. This conclusion offers a guidance for heat treatment process of DSS to be used in acidic environments.