Abstract: In 2008，the gas hydrate was discovered in the Qilian Muli permafrost region．As an important gas hydrate formation condition，permafrost has an obvious control effect on hydrate reservoir．Based on those permafrost parameters empirical formulas of the Qilian Mountains，the distribution characteristics of mean annual temperature，mean annual ground temperature and the thickness of permafrost in Muli are obtained by ArcGIS spatial analysis model for DEM．The results show the average annual temperature and annual mean ground temperature of the permafrost in Muli are in the range of－8～－5℃and－5～－2℃ correspondingly，and that the thickness of permafrost varies from 80 to 180 meters．As to the Juhugeng mining area，its average annual temperature and annual mean ground temperature are between－7 to－5℃ and－4 to－2℃，and the permafrost thickness is within the scope of 90～120m．The area around Datong Mountain has the lowest temperature and the thickest permafrost．Its average annual temperature and ground temperature are lower than－7℃ and－4℃ respectively，and permafrost thicker than 130m．Combined with the distribution of hydrocarbon source rock，we believe that the physiognomy transition zone between Muli basin and Datong Mountain is the most favorable area for the gas hydrate reservoir．