Since it is difficult to balance the speed and accuracy of the finite element simulation model of cutting processing， a dynamic mesh refinement algorithm for 3D finite element model is proposed. The functions of the algorithm include mesh refinement area judgment， mesh refinement and transfer of physics fields between new and old meshes. The algorithm is applied to the turning simulation of Ti2AlNb with the secondary development of Abaqus using Python， and the accuracy of the simulation model is verified through experiments. Compared with the simulation results of the local mesh refinement， the simulation using dynamic mesh refinement increases 7.3% in cutting force solution error and increases 0.2% in maximum stress solution error， with an increased 174.2% solution speed. The simulation operation speed is effectively improved while ensuring the calculation accuracy.