In recent years, extreme weather phenomena occur frequently in the world, and nuclear safety supervision departments are paying more and more attention to the ability of nuclear power plants to cope with extreme weather disasters beyond design criteria. For nuclear power plants in severe cold areas, how to ensure the safe and effective operation of relevant systems at extreme low temperatures needs special consideration. This paper investigates domestic and foreign nuclear power plant low-temperature regulations, standards and protection practices, analyzes and researches the adverse impacts of extreme cold weather on nuclear power plants, and studies and formulates low-temperature prevention targets for nuclear power plants as well as the corresponding acceptance criteria. At the same time, in combination with the goal of preventing low temperature, this paper carries out research on nuclear power projects at northern sites, sorts out the systems that need to be prevented from low temperature in the relevant reactor types, researches a set of reasonable and feasible analysis methods for preventing low temperature in nuclear power plants, and conducts research on generalized optimization measures for preventing low temperature in combination with the implementability, economy, and ease of operation.