Different models have been advanced for Cenozoic subsidence of the Qaidam Basin. A plausible mechanism，however，should account for two main problems： 1)How come the Cenozoic depocenters were kept in the middle portion of the basin； 2)what dynamic processes were responsible for subsidence of basin basement that was over 15 km deep. This paper summarizes the main geological characteristics of the Qaidam Basin and makes a review of previously proposed mechanisms. The crustbuckling model is further developed，suggesting that the formation of the Qaidam Basin could be primarily related to the folding or buckling of the upper crust of the northern Tibetan Plateau. This model satisfactorily explains localization of the depocenters and the relationship of the Qaidam Basin with adjacent intermontane basins during their development. It is thought that the southward subduction of lithospheric mantle might have led to the intense folding of the overlying detached crust.