The finite element method (FEM) has been widely used to model interaction of tillage tool and soil, because it is capable to provide an accurate prediction of tillage resistance. However, there is little research on modeling soil-root interaction in soil tillage practice. The object of this paper is to advance a well adaptable numerical assistance to simulate the root-soil interaction and predict the resistance force on a stubble cutting tool. A 3D dynamic simulation model using the FEM was established to predict the resistance acting on the stubble-cutting blade in the present work. Soil was modeled as elastic-plastic material, corn stubble was simplified as an assembly of lines with various diameters, and soil and stubble were tied together as a complex. Two stubble-cutting blades with different cutting edges and two forward velocities were examined using a FE computation model and verified experimentally by field tests. Comparison result of simulation and experiment showed that the prediction from the FE model agreed well with the measurements in a field test. It can be concluded from these results that the FE model designed in this work is capable of being used as a convenient and dependable prediction tool in analysis and development of the working capacity of tillage tool.