The rationality of cutterhead design of a 12 m slurry shield used in a shield tunnel and its construction adaptability to dense sandy stratum with high water pressure are very important. Firstly, the characteristics of largediameter slurry shield and the formation conditions dominated by dense sandy layer are introduced, a modified model for cutter load calculation is proposed by considering earth pressure and cutter penetration resistance and ignoring cohesion between sandy soils. By analyzing the influences of structure and back slurry pressure on cutterhead loads and torques, the input loads and torques of cutterhead are obtained. And then the simulation analysis model for largediameter slurry shield tunneling is established by ANSYS software, and the finite element analysis of normal tunneling, unbalanced loading tunneling and jamming releasing of slurry shield is carried out. The results show that the stress and deformation of cutterhead are the largest under unbalanced loading tunneling condition, and the maximum stress occurs on the joint of the main arm support rib and flange at the lower half of the cutterhead, reaching 128.46 MPa; the maximum deformation occurs to the edge of the cutterhead, reaching 2.85 mm; and the performance of cutterhead can meet the design requirements.