According to the characteristics of cutter rock,the mechanical model considering the step distance and cutting thickness and the 5 000 kW cutter physical model and finite element model are established.The force when the cutter back cutting the rock and the stress and deformation of the maximum power are analyzed.The calculation result shows that the maximum deformation of the 5 000 kW cutter is 1.84 mm and the maximum stress is 140.5 MPa under design conditions.The deformation and stress meet the stiffness and the strength requirement to verify the design rationality.