Area and condition variation of three kinds of permafrost in 2099 are simulated by integration of temperature data and modern permafrost distribution in Tibetan Plateau. The conclusions shows that in condition of 1.8ºC rising of annual average air temperature, the total area of permafrost will be 83.4% of today, the continuous permafrost will shrink to the east of 76.6°E, the sporadic permafrost melts greatly in southeast of plateau, and the mountainous permafrost has obvious degeneration in Pamirs and Himalaya Mountain area. While in condition of 4ºC rising of annual average air temperature, the total area of permafrost will be 73% of today, the continuous permafrost will shrink to the east of 77.4°E, the sporadic permafrost degenerates slightly in middle area, the mountainous permafrost melts greatly in Qilian Mountain, and it only could be found in some high altitude places such as Pamirs, Himalaya Mountain and Hengduan Mountain. In condition of 6ºC rising of annual average air temperature, the total area of permafrost will be 50.8% of today, the continuous permafrost will shrink to 78°E, the sporadic permafrost only could be found in middle-west area, the mountainous permafrost appeares in some extremely high area slightly.