In this chapter, the general characteristics of permafrost and cryogenic features are described, and the degradation of permafrost is simply analyzed too. The permafrost in Mongolia lies at the southern edge of Siberian permafrost with different permafrost zones. The distributions of continuous and discontinuous permafrost zones are usually controlled by the climate in Mongolia while the local environmental factors are mean force that persist the existences of sporadic and isolated permafrost zones. Due to the location and climate condition, permafrost temperature in Mongolia is mostly close to 0 °C, and making it vulnerable to climate warming and anthropogenic impacts. The results from permafrost monitoring indicate that permafrost in the country has degraded more intensively during the last decades and it has a negative effect on ecosystem services, because the permafrost in Mongolia overlaps considerably with forest and the source area of river water. In Mongolia, several features of cryogenic develop in the permafrost region, such as patterned ground forms, frost cracking, ice wedge, karst, thermokarst lake, aufeis, pingo, seasonal pingo, hummock, frost heave, frost sorting, dog hole.