Cold hardening is a very effective strategy used by insects to survive cold temperatures. Rapid cold hardening can significantly enhance the cold tolerance of insects within a short period of time, thereby enabling them to cope with fluctuating climatic conditions. Cold hardening is therefore an ecologically significant trait of insects in the context of global warming. Since its first discovery, rapid cold hardening has been widely studied, and great progress has been made in understanding the mechanism underlying this adaptation, especially in recent years. This paper reviews the latest research on rapid cold hardening, including its characteristics, physiological, biochemical and molecular mechanisms, and its ecological significance, in order to provide suggestions for further research on this subject.