Abstract: Based on the information from lithology, gravity, magnetic field and magnetotelluric depth measurement and on analyses of basement structural characteristics in Qaidam basin, the study shows that the basin was shaped with in the stress field of compressional structures following Indo-China movement, in which well-developed faults were brought about. And Qilian southerm marginal fault, Qaidam northem marginal fault, Hubei-Lingjian-Dahuo fault, No. XI fault and Kunlun northem fault are confirmed along NW distribution and controlled by a compressive inter-ramping effect between Qilian moutains and Kunlun Moutains; while along NEE -NE direction, the development of A'nan fault, Tardin- Yuka fault and Germu-Xitieshan fault occurred due to intensive influences of Arkin structural belt. These two varied basement structures in orientation when composite and superimposed each other could have a major significance for controlling the development and distribution of caprock sedimentation constructions, resulting in the fact that at Qaidam's Mesozoic and Cenozoic basins have zonations with NW -SE strike and segments along NE -SW direction, which may, in a direct or indirect sense, control the formation, distribution and accumulation or reservoir of hydrocarbon resources in Jurassic, Tertiary and Quaternary.

Key words: Qaidam basin, Basement structure, 0il and gas resource, Mesozoic, Cenozoic