Compared with conventional dredging projects，ecological dredging construction has the requirements of high dredging accuracy，less sediment disturbance，and high excavation concentration.For this production demand，this paper develops an environmentally friendly spiral dredging tool.The theoretical excavation concentration of the dredging tool is more than 60%，which meets the construction requirements.According to the design requirements，the strength and stiffness of the key structures of the dredging tool should meet all working conditions，but it cannot be directly verified by mathematical calculation.The paper uses the finite element method to analyze the complex structures and utilizes the overall modeling method to construct the simulation model.In addition，it analyzes forces by the enumeration method and simulates the stress and deformation of the dredging tool under different working conditions，so as to evaluate the strength and stiffness of the dredging tool.The results show that the strength and stiffness of each structure of the dredging tool meet the needs of the operation.At the same time，the paper finds that there is a displacement difference between the upper and the lower hinge point of the depth cylinder and the direction adjustment cylinder，and the deformation of the far-motor side and near-motor side of the spiral knife group shaft is different.Finally，the paper proposes that the hydraulic cylinder deformation compensation can be realized by designing universal joints to prevent the hydraulic cylinder structure from damage.