Abstract: Utilize the Unfold of the Fault Throw along fault strike and the Back strip applied on structure research, viz. BUFT(the Back strip of the Unfold of the Fault Throw along fault strike) to judge the connect manner and level of half grabens, locating the point of terrigenous supply, combining structural ridge with geochemistry to judge the pathway of hydrocarbon, supervising the exploration of hydrocarbon. After analyzing the south boundary fault at Zhu Ⅲ Depression in the Pearl River Mouth Basin, the developing patterns of the boundary fault in Zhu Ⅲ Depression is considered includes four patterns: (1)Basic;(2)Series connection; (3)Transfer; (4)En echelon. The different patterns have different terrigenous supply. It is clear that on the Shenhu massif have the migrating pathways of three hydrocarbon states,viz. Wencheng Sag B-QH36-2,Wencheng Sag B,A-WC15-1?CC2-1, Wencheng Sag A-KP1-1 and four prospects, viz. QH36-2, WC15-1, CC2-1 and WC20-1, by making integral analysis.