Abstract: Marine engineering equipment operates permanently in a multi-factor coupled corrosive environment characterized by high hydrostatic pressure, low dissolved oxygen, low temperature and microbial activity. Traditional single-principal-element alloys have approached their performance limits due to the single component, insufficient stability and high localized corrosion susceptibility of their passive films. The multi-principal-element design of FCC high-entropy alloys (HEAs) endows passive films with multi-component synergistic characteristics, and high configurational entropy stabilizes the solid solution matrix. The synergistic effect of the above two features enables FCC HEAs to exhibit promising corrosion resistance application potential in complex marine working conditions. This paper systematically reviews the corrosion behavior and corrosion resistance mechanism of FCC HEAs in marine environments. First, the constituent elements of FCC HEAs are classified into five categories, including matrix alloy elements, low-melting-point metal elements, refractory metal elements, non-metallic elements and rare earth elements. The differential influence rules of each type of element on the composition and stability of passive films, pitting resistance and interphase galvanic corrosion susceptibility are summarized. Second, the effects of precipitated phases and microstructures on corrosion resistance are discussed, and the strengthening mechanism of nano-scale coherent precipitated phases that simultaneously improve the strength-plasticity synergy, localized corrosion resistance and hydrogen embrittlement resistance is concluded. Subsequently, based on the process methods including additive manufacturing, synergistic processing deformation and heat treatment, as well as shot peening, this paper summarizes the research progress of these processes in regulating the formation and repair capability of passive films by adjusting grain size, elemental segregation and residual stress distribution. On this basis, focusing on three typical extreme working conditions of corrosion-wear coupling, deep-sea multi-factor coupling and hydrogen-induced damage, the failure mechanisms of FCC HEAs under multi-field coupled environments are summarized. It is indicated that the corrosion failure rules of FCC HEAs under the above working conditions differ from those in single static corrosion environments, and the composition design needs differentiated trade-offs according to targeted service conditions. Finally, the application status of machine learning in the design of corrosion-resistant high-entropy alloys is reviewed. Existing models are mostly based on data obtained from single media under normal pressure, which cannot accurately predict the corrosion behavior of FCC HEAs under deep-sea multi-field coupling. Future research needs to optimize feature engineering combined with physical cognition to improve the generalization ability of models. This paper holds that for the long-term service of marine engineering, FCC HEAs urgently need to solve the matching problem between composition and service stability under extreme working conditions, and accelerate the construction of multi-factor coupled performance databases to promote the engineering transformation of laboratory achievements.