In view of various threats of strong electromagnetic environment to ship information equipment under electromagnetic space countermeasures and the requirement of electromagnetic protection, the mechanism of strong electromagnetic environment effect and basic protection principle of ship electronic equipment are prospected. The principle and development of frequency selective surface, energy selective surface and new electromagnetic shielding materials used to reduce the coupling of radiation field to ship electronic system are described; the principle and development of RF front-end protection technology based on gas discharge tube, semiconductor limiter, RF high power limiter technology based PIN diode and electromagnetic pulse protection technology based on plasma for suppressing the strong electromagnetic pulse transmission on the "circuit" are also introduced. This paper analyzes the applicability and advantages of different protection technologies in the design of ship equipment for strong electromagnetic pulse, and forecasts the future development trends of strong electromagnetic environment protection technology for ship equipment, provides support for the design of strong electromagnetic environment protection for ship equipment.