This paper deals with the Rb-Sr biotite isochron ages of the granitoid in the Sanshiliying-fang area of the Karakoram and Kunlun Mts. region. It has peen found that the Rb-Sr biotite isochron age of the diorite is 539 Ma, belonging to the Cambrian period, and that the Rb-Sr biotite isochron age of the Saidulla granodiorite is 215 Ma, being equivalently of the late Trias-sic period. The results also show that there exists the granitoid of Early Paleozoic Era in the Gonggol-Akagazi petrographical belt.