Abstract: On the basis of an analysis of geological and geophysical data obtained by petroleum exploration in the South Poyang depression in recent years,the authors propose that the basining and tectonic evolution of the South Poyang depression were controlled by the activities of the Ganjiang fault zone under the constraint of the Yanshanian tectonic framework.The main tectonic activities were strike-slip movement and extension.The model of the tectonic evolution of the Nanchang subbasin is as follows:in the Lengshuiwuan(K₁l),the subbasin was a strike-slip-pull-apart basin;in the Zhoujiadianian(K₂z) to early Nanxiongian(K₂n¹) it was a sinistral strike-slip basin;at the end of the early Nanxiongian a tectonic turn took place;in the mid-late Nanxiongian(K₂n²⁺³) it changed to a dextral strike-slip-extensional basin;in the Qingjiangian(E₁q) it became a new downfaulted basin.According to the features of the basining and tectonic evolution of the Nanchang subbasin,the authors suggest that the large-scale sinistral strike-slip movement of the Ganjiang fault zone occurred in the early-mid Late Cretaceous and the turning point from the sinistral strike slip movement to dextral strike-slip movement occurred at the end of the Late Cretaceous early Nanxiongian(K₂n¹).