Abstract: The Jiuxi basin is located within the triangle area which is surrounded by the North Qilian fault to southwest and Altyn Tagh fault to northwest, and is of an important significance in understanding the Cenozoic tectonic-sedimentary evolution of the northern Tibetan Plateau. In this paper, we carried out a detailed study of sandstones of the Eocene Huoshaogou Formation in the Hongliuxia and Huoshaogou sections, using detrital components, morphology and cathodoluminescence of quartzs. The results show that the rock fragments, quartze detritals and feldspar detritals of the sandstone from the Huoshaogou Formation are typical characteristics of the metamorphic rocks origin. In combination with the geological, structural background and palewater features of the Jiuxi basin, this study systematically analyzed the regional rock features of Altyn and Qilian mountains, which provided the materials for studying the Huoshaogou Formation in the Jiuxi basin. It can be concluded that the provenance of the Huoshaogou Formation in the Jiuxi basin might derive from the Altun Mountains, and the offset of the Altyn left-lateral strike-slip fault should be more than 450 km.