The surface passivation of Mercury Cadmium Telluride (MCT) materials is one of the crucial steps for fabricating photoconductive and photovoltaic detectors. Practical MCT devices need stable and reproducible passivated surfaces and the surface potentials which meet their performance requirements. The research progress of the surface passivation of MCT materials is presented. The basic concepts of the passivation of MCT materials are described. The growth methods, interface properties and parameters of some passivation layers are discussed.