The lower sandstone part of Eogene Kumugeliemu Group in Kuqa depression can be divided into three depositional belts, namely the fluvial fan coarse de posit-incised channel filling-fluvial-delta system of South Tianshan Mountain marginal grit belt, the near fluvial fan-fan delta deposit of Wensu uplift margin belt, and the incised valley filling-fluvial-delta shallow lake shoal bar of Tabei uplift belt. There are dry salt lake-lagoon-sea gulf sediments in the middle of the depression. A source rock analysis shows that the western Wensu uplift, northern south Tianshan Mountain and continent eroded source rocks of Tabei uplift comprised the major source rocks of Eogene Kumugeliemu Group sediments. The clastic materials mainly came from South Tianshan Mountain and Wensu uplift recycle orogenic belts. The thrust orogenesis and the uplift of the northern margin of the depression formed a prolonged source rock supply area. Along the northeastern margin of the depression, there was developed a fluvial fan of great thickness. The western Wensu uplift provided source rock in the early period, and there was developed a small marginal fan or a fan-braided fluvial delta along the uplift margin. The Tabei uplift also provided some source meterials in the early Eogene, and the erosion of the crystalline basement near Kela 201 well was the major material source of southern continent eroded area. The substance of Quele 1 and Yangta 5 well came probably from the above three source rock belts forming a mixed source area. The result of the source system analysis is consistent to the global paleo-structure and paleogeographic framework. The eastern basement was much higher than western Eogene Kuqa depression, and hence there existed the migration of large amounts of terrigenous detrital materials from east to west. The paleo-structure framework combined with the eastern and western uplift belts and t he northern marginal foreland frontal deep belt determined the source system and the paleolithologic distribution.