The mechanical performance of the cutterhead structure under normal working conditions is analyzed by ANSYS Workbench so as to provide reference for optimal design of cutterhead of an EPB shield used in Lanzhou Metro. According to the obtained contours of equivalent stress, total deformation and fatigue life, the weakest positions of static and fatigue strength of the cutterhead (the outer corner of corbels near the interface with the back of faceplates) and the poorest positions of stiffness (the outer edge of two faceplates without muck outlet) can be decided. The static strength and nominal fatigue life in the weakest positions of the cutterhead under normal working conditions can be increased by 71% and 265% respectively and the deformation of the outer edge of faceplates can be decreased by about 25% in case the opening ratio of the cutterhead increases from 35% to 37% by structural improvement and size optimization of the cutterhead.