Abstract: In order to investigate the mechanism of reversed structure deformation in the southwestern Qiongdongnan Basin, we carried out an analogue modeling experiment. The influence of weak body and tectonic stress on reversed structure deformation in the Qiongdongnan Basin is discussed upon the basis of the modeling results. The modeling results suggest that the weak body plays an important role in the deformation of reversed structures no matter it is in the extension stage or compression stage, which marks the time when the reversed structural deformation first appears and propagates in weak zone. As the Red River fault in NW-direction slips, the northwestern Qiongdongnan Basin was compressed which led to reversed folding from northwest to southeast. Based on comparison of modeling results with the actual structures, it is concluded that the deformation of the reversed structure in southwestern Qiongdongnan Basin is mainly influenced by the existence of the weak body and the northwestern Qiongdongnan Basin was compressed because of the slipping of NW Red River fault and the compressional tectonic stress which may come from the revolving of the Indochina block.