Because of the latent energy prospect and its impacts to the climate and the environment, many countries began the studies on natural gas hydrate in permafrost regions and achieved great research progresses subsequently. The relations between natural gas hydrate and permafrost are explained in this paper, as well as the reserves of natural gas hydrate in permafrost regions and the present research situations of natrual gas hydrate in representative permafrost regions. The results indicated that the formation conditions of natural gas hydrate such as temperature and pressure were restricted by permafrost; and the natrual gas hydrate with self-preservation was discovered inside the permafrost layer. The accumulation and transfer of free gas in sediment were influenced by permafrost；and besides, the thawing of permafrost can raise the pore pressure. The present estimations of the natural gas hydrate reserves in permafrost regions were not integral or all-around which were only made in some representative permafrost regions. The estimation showed that the natural gas hydrate reserves in Northslope in Alaska, US were about 1.0×1012~1.2×1012 m3, about 1.6×1013 m3 in Beaufort, Makenzie Delta, and about 1.7×1013 m3 above 250 m depth in west Siberia. The existence of natural gas hydrate in Qinghai-Tibetan Plateau is an important issue which demands prompt understanding.