Passivation film of stainless steel in the marine environment is easily damaged, leading to occurrence of localized corrosion. Cathodic protection is an effective and reliable means of protection commonly used in marine environment, which can form an effective protection for stainless steel. In this paper, the development status of cathodic protection of stainless steel in marine environments was reviewed and it was found that cathodic protection could not only avoid the occurrence of localized corrosion, but also have good inhibitory effect on existing pitting and crevice corrosions, however, different cathodic protection potentials would influence the stainless steel substrate and thepassivation film. When the cathodic protection potential was too positive, it would fail to effectively protect the stainless steel substrate. With the negative shift of protection potential within a certain range, the stainless steel could be effectively protected, keeping the passivation film intact. If the protection potential was too negative, hydrogen evolution reaction occurred, with the risk of hydrogen induced cracking, and there was the risk of passive film activation, resulting in uniform corrosion. Currently, a large number of studies were focused on determination of the potential protection scope of stainless steel in a certain environment, but the protection potential range span is generally quite large, therefore in the actual implementation of protection, there is still no clear selection criteria of the applied potential.