Apatite fission track ages and track lengths for 7 samples from the Karibasheng and Kuzigan granite in the west Kunlun Mountains are reported in this paper. The results suggest that this area undergo pulsatory uplift since 5 Ma B P. The uplift rate was about 0. 1 mm/a during 5'-2 Ma B P, and increased to 2~3 mm/a after 2 Ma B P. 6 samples'fission track ages increase with the sample's elevations. The single grain age of one sample shows a wide range; it furnishes the information of early cooling history related to the uplift. Track length analysis shows that all the samples were in the partial annealing zone during the uplift. From a geological point of view, it is inferred that before 5 Ma, the uplift was related to the collision between the Indian plate and the Euroasian continent and after 2 Ma the uplift was due to the thermal isostatic adjustment of the Qinghai-Tibet plateau.