The early permian reef belt is distributed in the southern side of eastern Kunlun, north area of Qinghai-Tibet Plateau. The core-reef facies of the reef extends from Tuosuo Lake to Huashixia. Lots of reef breccia was found at the southern slope of the core-reef belt, and to the north of the reef belt there is back-reef limestone. Cacisponges, hydrozoa, bryozoa, Tabulozoa, Tubiphytes and red algae are the main frame-building organisms. Archaeolithoporella, laminated blue-green algaes, Tabulozoa and Tubiphytes played a role of binding or encrustating. There are many kinds of epibiont in the reef, including brachiopod, gasteropod, foraminifera, echinoderm and simple coral. The type and the characteristics of the reef-building organisms in eastern Kunlun and Animaqing are basically the same as those in the south of China The early permian reef belt is distributed in the southern side of eastern Kunlun, north area of ​​Qinghai-Tibet Plateau. The core-reef facies of the reef extends from Tuosuo Lake to Huashixia. Lots of reef breccia was found at the southern slope of the core-reef belt, and to the north of the reef belt there is back-reef limestone. Cacisponges, hydrozoa, bryozoa, Tabulozoa, Tubiphytes and red algae are the main frame-building organisms. Archaeolithoporella, laminated blue-green algaes, Tabulozoa and Tubiphytes played a role of binding or encrustating. There are many kinds of epibiont in the reef, including brachiopod, gasteropod, foraminifera, echinoderm and simple coral. The type and the characteristics of the reef-building organisms in eastern Kunlun and Animaqing are basically the same as those in the south of China