Bottom mud of environmental dredging will be mixed with harmful pollutants. The disturbance effect produced by the traditional dredging cutters will lead to the diffusion of pollution sources and the poor dredging effect，so domestic environmental dredging projects urgently need dredging equipment suitable for construction requirements. Using the method of combining theoretical research and finite element technology，an environmental-friendly dredging equipment is designed. The finite element method is used to simulate and analyze the structural deformation and stress of the equipment under different working conditions，and the lightweight optimization of the machine tool is carried out. The research shows that：1）The wing gates and reamer sets of the new dredging cutter bear greater forces，so their strength and rigidity need to be strengthened. 2）The supporting parts are in better stress condition and can be lightweight design. 3）The force of the base part is relatively bad，and the base part needs to be strengthened.