Samples collected from Southern Xizang were determined by K-Ar method. Basing on these isotopic data and making use of geological materials available we have found that the northward drifting of the Indian Plate is a continuous process during Late Cretaceous to Pleistocene in this region. The spatial distribution of dating data also shows that the Indian Plate and the Eurasian Plate moved against one another.As to the crustal movements involved in the tectonic history and the recent tectonic framework laid down during the Mesozoic in this region, we are inclined to divide them into four stages: (1) the Late Yanshan movement of Late Cretaceous, 119.3-64.5 m.y.; (2) the episode Ⅰ of Himalayan movement in Eocene, 54.9-42.0 m.y.; (3) the episode Ⅱ of Himalayan movement in Oligocene, 35.6-26.8 m.y. and (4) the episode Ⅲof Himalayan movement from Miocene to Pliocene, 24.7-6.4 m.y.