Abstract: It possesses a great significance for optimizing tool design and improving cutting efficiency to fathom the internal mechanism of soil deformation and soil-tool interaction during the rotary cutting process of cohesive soil. Taking a nonlinear elastoplastic constitutive model with damage characteristics to describe the mechanical properties of cohesive soil and adopting coupled Eulerian-Lagrangian method to simulate the deformation and failure behavior of cohesive soil, the dynamic rotary cutting process of cohesive soil was directly simulated. And then some rotary cutting experiments were carried out on cohesive soil to verify the numerical simulation results. The numerical simulation and experimental results under different working conditions all show that the rotary cutting process of cohesive soil can be regarded as a continuous large deformation process of the soil material relative to the tool. In the range of cutting angles from 30° to 60° and cutting depths from 5 mm to 15 mm, the steady-state average value of the rotary cutting moment of cohesive soil increases with the increase of either cutting angle or cutting depth. The proposed methods and research conclusions possess important reference value to the design of rotary cutting implements for cohesive soil.