Located in East Junggar area, Xinjiang, the Beiledukuk ore belt is an independent tin metallogenic belt discovered for the first time in northern China in recent years. It has four independent tin deposits, several tinoccurrences and one tungsten occurrence. The primary tin deposits consistof quartz vein tin deposits related to S-type granites and tin depositsassociated with Artype (alkaline) granites. The belt strikes northwest alongthe northern side of the Kalamaili suture zone between Junggar and Yemaquan.The paper mainly discusses geological characteristics of the Hercynian stanni-ferous and tin-absent granites in the tin metallogenic belt. It is believed thatI-, S-and A-type granites of this area were formed during the Hercynian move-ment. The highly differentiated and evolved S-and A-type granites -elated totin mineralization are poducts of the late orogenic-postorogenic stage, formed on the basis of further evolution of early-stage (orogenic) I-and S-type gra-nites. The integrated criteria for discriminating between ore-bearing and barrengranites have been summarized, which are conductive to the search and study of tin deposits of the same types in this area and its neighboring areas.