Abstract: The tectonic affiliation of Qamdo B1ock between the Gondwana and Eurasia remains controversia1, which involves mainly the determination of the northern boundary of Gondwana and the palaeobiogeography of Qamdo B1ock. Fusulinid fauna, a kind of benthiclife, is applied to the palaeobiogeography study in this paper. Based on abundant of fusulinid fossils from Early Permian Schwagerma cushman1 fauna to Late Permian Paiaeofusuiina slnensls fauna in volcano-sedimentary sequences from southern Qinghai, it is proposed these fusulinid faunas have always been the warm-water Tethyan type, showing more similari- ty with the counterpart from South China, and has not beenlinked to the fauna from the Gondwana. The fusulinids from the Qamdo B1ock should be1ong to the South China Subprovince, Cathaysian-Tethyan Province, Tethyan Realm in palaeobiogeo- graphic affiliation. The Lungmu Co-Shuanghu-Lantsangjiang Suture Zone in the Early Permian is proposed as the southern boundary of the Cathaysian-Tethyan Province(warm-water type) in the Tibetan Plateau(or the boundary of South China Sub- province and the northern Tibet Subprovince characterized by a mixed warm and cold biota). This suture zone is the division be- tweenTethyanand Gondwana Realms which was changed in the Middle and Late Permian and can not be regarded as the boundary of Realms, although a minor difference between the fusulinid faunas from two areas separated by the suture zone sti11 existed.Furthermore, the similarity of the faunas from both sides of Jinshajiang Suture Zone shows the zone is not the barrier zone which prevented the migration of benthic biota and can not be regarded as the boundary of palaeobiogeographic provinces.