The ground layer of the No.2 Metro Line in Guangzhou has the characteristics of mixed ground conditions： more curves and big gradient variation. So it is difficult to excavate successfully and control the tunneling direction and shield tunneling attitude. Furthermore, it is also difficult to prevent segment crack and local failure and dislocation of segment. In order to control the tunneling direction and shield tunneling attitude more successfully, the reason of direction warp was studied and the actual measure data of Yue-San shield tunneling zone were analyzed. At last, the reason and the rule of direction warp were got and many methods to control shield tunneling attitude were tried. The main cause of segment crack and local failure of segment, were also studied with numerical simulation, and methods to control segment crack were brought forward.