Abstract: Aiktik group，distributed at the western end of South Tianshan Mountains in China，is an important lithostratigraphic unit involved in south Tianshan orogen. It is separated from the adjacent rocks with faults. Generally, the geologists classified it into Upper Carboniferous according to Pseudostaffella sp.，Profusulinella sp. and Fusulinella sp. found from the limestone and sandy limestone of Aiktik. Our radiolarian fossils were obtained from the chert samples collected from Haladaok section located at the upper stream of Tuoshihan river. The fossils include mainly Albcillla undulata Deflandre, Albillla paradoxa Deflandre, Albaillella sp. aff. A. paradoxa Deflandre, Albaillella sp. cf. A. deflandrei Gourmelon, Albillella sp., Albillella excelsa Ishiga, Kito and Imoto (?)， Belowea variabilis (Ormiston et Lane), Callella cf. C. parvispinosa Won, Entactinia cf. E. tortispina Ormiston et Lane, Entactinia aff. E. tortispina Ormiston et Lane， Entactinia variospina Won， Entactinia sp.， Eostylodictya rota (Won)，Latentifistula impella (Ormistone et Lane) (?)， Latentifistula turgida Omiston et Lane， Latentifistulidae. gen. et. sp. indet. 和 Polyentactinia cf. aranea Gourmelon. In which, Albaillella excelsa Ishiga, Kito and Imoto (?) isa Late Permian species with some element of unsure as there is only one unwell-preserved individual fossil of this species found so far. And two radiolarian assemblages can be identified out from the other fossils. One is the early Early Carboniferous assemblage represented with Alballella undulata Deflandre, Alballella paradoxa Deflandre and Albailella sp. cf. A. deflandrei Gourmelon. And the other is the late Early Carboniferous assemblage represented with Eostylodictya rota (Won). This is the first discovery of radiolarian fossils in Aiktik group, also the first discovery of Late Permian radiolarian fossil in Chinese South Tianshan. Meanwhile, this is the current most-west sampling place of radio larian fossil in Chinese South Tianshan.

Key words: south, Tianshan Mountain, Aiktik group, radiolarian, Late Permian, Early Carboniferous, Middle Carboniferous