The occurrence of thermokarst lake is an indicator implying the permafrost warming. A study of  thermokarst lake and their thermal effect will become an important basic work that responds to the permafrost hazards induced by the climate changes and the anthropogenic activities on the QinghaiTibet Plateau. Based on SPOT-5 satellite image data, we interpreted and obtained  the area and quantity of thermokarst lakes from Chumaerhe to Fenghuoshan Mountain section along the Qinghai-Tibet Highway under the ArcGIS platform in this paper. The result shows that these thermokarst lakes have mainly spread in Chumaerhe High Plains and Beiluhe Basin and approximately 80% lakes have been developing in rich-ice permafrost regions. The thermokarst lake influences  the permafrost through downward and lateral heat transfer. The downward heat transfer  accelerates the thawing of permafrost and the formation of an open-talik, the lateral heat erosion will cause the permafrost warming at lakeshore and expand the scope of the heat-affected. The modeled result of a typical thermokarst lake in Beiluhe Basin shows that the lake has always released the heat to lakeshore in a whole year. If the thermokarst lake is  close to the roadbed, it will cause influence on the  stability of roadbed, especially the lateral thermal erosion often leads to the temperature increases of frozen soil subgrade and induces  the embankment disease.