Voronoi-based non-periodic porous structures resemble trabecular bone and are widely used in bone scaffold design. To clarify the influence of strut-diameter morphology on compressive mechanical properties, two Voronoi porous structures with identical porosity, namely uniform-strut and non-uniform-strut structures, were constructed. Their quasi-static compressive and compressive-fatigue behaviors were analyzed using the finite element method. The results showed that the uniform-strut structure had a more homogeneous stress distribution and higher stiffness in the linear elastic stage. The non-uniform-strut structure exhibited higher load-bearing capacity and energy absorption during compression failure. Under compressive fatigue loading, the uniform-strut structure generally showed a longer fatigue life. The uniform-strut structure is suitable for implant scaffolds and prostheses under the conditions of long-term cyclic loading and controllable mechanical matching; the non-uniform filament diameter structure is more suitable for applications under the conditions of impact resistance and energy absorption buffering. These results provide a reference for the selection and optimization of Voronoi biomimetic porous structures under different service requirements.