Electromagnetic railguns have an advantage over traditional chemical propulsion weapons, in that the projectile can be accelerated to extremely high speeds and effective damage can be achieved. However, during the launch from an electromagnetic railgun, the ammunition will be subject to a harsh environment, including very strong and violently changing electromagnetic fields, high-g acceleration impact, high temperatures, and so on; and thus, the reliability of the fuze is threatened, and the safety and damage effectiveness of the ammunition will be seriously degraded. In this paper, the harsh environment during the launch process is first reviewed, including the experimental data, the modeling, and simulation of the multiphysics fields. In particular, the coupling effect of these multiphysics fields are revealed, which aggravates the extreme environment. Furthermore, this paper reviews the protection of fuzes against strong magnetic fields and high-g impacts from three aspects, namely, materials, devices, and systems, and presents prospects for future research. This review will guide studies on the protection of fuzes and the stability of ammunition, as well as promote the effectiveness of electromagnetic railguns.INDEX TERMS Electromagnetic launching, fuze, reliability, harsh environment of multiphysics fields, electromagnetic shielding, anti-high-g impact technology.