Permafrost is mainly distributed in high latitude and high-altitude areas, most people know little about it, while permafrost covers vast areas accounting for about a quarter of the land area of the Northern Hemisphere. As a product of cold climate, permafrost is sensitive to climate change, and global warming has led to the wide permafrost degradation in the world. The permafrost degradation can also have important effects on ecosystem changes, hydrological process, and many important infrastructures, and also have feedback effects on climate. Nowadays, many studies have been conducted in the permafrost both in the Arctic and in the Qinghai Tibet Plateau, while there are still many scientific questions need to be resolved. For better understanding of the future climate change, as well as design and implement of sustainable development approaches, more attentions should be paid on the permafrost change and its impact.