<p>This paper proposes a hybrid unstructured mesh generation method for turbomachinery simulations, aiming to overcome the limitations of conventional approaches in geometric adaptability, size control, viscous boundary-layer resolution, and automation. A hybrid surface representation framework is first constructed, in which the discrete surface representation serves as the background mesh for size control, while the continuous surface representation defines the geometric boundary for mesh generation. A unified topological data structure is then established to manage the discrete representation, continuous representation, and mesh model in a consistent manner. To handle the complex geometric configurations of turbomachinery, feature recognition and local mesh refinement techniques are developed, and the size function is defined on the optimized background mesh. An efficient size-function smoothing strategy is further proposed to ensure a smooth transition between regions with different mesh densities. The proposed method is validated through numerical simulations of several representative turbomachinery cases, and the predicted results are compared with experimental data as well as with those obtained using the commercial software packages ICEM-CFD and Pointwise. The results demonstrate that the proposed method achieves comparable or superior mesh quality while significantly improving mesh generation efficiency, and the simulation results show good agreement with experimental data.</p>