Abstract: Based on the structural ewolution and goological framework in northern margin rift of Qaidam basin, this paper presents that the overall course of faults development in middle Qaidam is the main power for control ling the superimposition and assemblage of Mesozoic and Cenozoic basins, the deep sodimentary structure of Mesozoic and the reverse structures during Himalayan movement in this rift, and ilustrates that the petroleum system in it is characterized by side-by-side pattern in space and by continuous pattern in time. Furthermore,some countermeasures and saggestions are made,which are of significance for expleration of the rif-lilce reservoirs in this area.

Key words: Qaidam basin, Qaidam rift, petroleum system, petroleum exploration