The granitoids in central and southern Xizang can be divided fro m north to south into three belts, i. e.the Gangdisi belt, the Lhagoi-Gangri belt and the Himalayan belt. Though belonging unexceptionally to the talc-alkaline series, the granitoids are characterized by different rock types in different belts with gre- nodiorite occurring m ainly in G ang disi, gneissic two-mica granite in Lhagio-Gangri and muscovite granite and tourmaline granite in Himalayan. In addition, zircons from granitoids have diverse typomorphic characteristics in different belts: (1)the content of zircon in granitoids gradually decreases fro m north to south: (2) the Zr/Hf ratio of zircon decreases as the acidity of the rocks grows higher and the age of the rocks becomes younger: (3) the elongation coefficient of zir- con rises with the increasing Si一K+Na contents of the granitoids; (4) (100) and. (111) crystal faces of zircon are m uch developed where Si, K and Na contents of granitoids are relatively low in the Gangdisi belt, while (110)，(311)and(131) faces of zircon aie extensively seen in the Lhagio.Gangri and the Himalayan belt whose granites have higher contents of Si, K and Na: (5) As for REE, the zircon is dominated by HREE, with a HREE/ REE proportion of more than 80%。