Zhenwu fault is an important basement fault in Gaoyou sag，which is crucial to understanding the structural characteristics of Gaoyou sag. Based on the fault interpretation and the regional stress field，the evolution of Zhenwu fault could be divided into three stages：compression stage，inversion stage and extension stage. During the compression stage，Zhenwu fault was a thrust fault formed by the collision of the Indosinian plate；during the inversion stage，Zhenwu fault evolved inherently into Zhen① fault and Wu① fault which differ from each other；during the extension stage，a series of secondary faults formed under the influence of Zhen① fault and Wu① fault，such us Zhen② fault and Wu② fault，which resulted in the formation of Zhenwu fault zones and Wubao fault zones. The results of sandbox experiment modeling Zhenwu fault during the extension stage show that Zhenwu fault，as the basement fault，and regional stress field are the most important two factors that control the evolution of southern boundary fault zones in Gaoyou sag.