Of Uighur Manuscript Or. 8212-108, British Museum, brought back by Sir Aurel Stein, the parts 2a-16b and 37b-38a have never been studied before. The first part contains a complete Buddhist text, composed by V’BSU baγšï and titled 心 tözin uqttačï nom. It remains unidentified with any Buddhist text in other languages, but four quotations from Śūraṅgamasamādhinirdeśa (Shou leng yen ching) and Gaṇḍavyūha (Hua yen ching) in it correspond to the Chinese versions. From linguistic point of view, Buddhist terms occurring in it are interesting. They are a mixture of Uighuric, Sanskrit and Chinese words, allowing us a glimpse of how the Uighur language adopted Buddhist terms. The second part is a diagram of Buddhist sectarian divisions mentioned in the Theravāda scriptures. The content of this diagram, judged from the number of the sects and the order of their schisms, appears to be closest to Samayabhedoparacanacakra (I pu tsung lun lun or Shih pa pu lun). This diagram is of considerable importance since no other Uighur text has been found to refer to the division of Buddhist sects.