<p>This paper proposes a new surface treatment method for titanium alloys using a rotational impact composite process. Finite element simulation was employed to analyse the influence of rotational impact on the surface stress field. The results show that the stress distribution induced by rotational impact is more uniform than that achieved by traditional impact. Rotational impact is a strengthening process that involves the combined action of compressive and shear stresses. Residual tensile stress on the surface is effectively eliminated after rotational impact treatment. Increasing the number of rotation cycles leads to a more continuous stress distribution on the material surface, which promotes a continuous distribution of residual compressive stress. Shear stress primarily acts on the near-surface region, while compressive stress affects deeper areas of the material. The residual stress field on the material surface results from elastic-plastic deformation. The revelation of the above stress field characteristics demonstrates that enhancing surface strength through rotational impact is a viable approach. Furthermore, the analysis of the stress field via finite element simulation provides a theoretical basis for designing rotational impact cutting tools. Finally, the conclusions drawn regarding the patterns of stress field variation in this study offer guidance for optimizing rotational impact process parameters. Therefore, this study is of great significance in guiding the development of new milling processes and tools.</p>