<p>Metal matrix composites are widely used in the aerospace field because of their high specific strength, stiffness, and good temperature resistance. SiC/Ti composites have been successfully applied in aero-engine turboshafts. In order to study the failure models and influencing factors of SiC/Ti composite shaft structure under torsional loading, torsional strength and fatigue experiments of SiC/Ti composite under positive/reverse torsional loading were carried out in this study. The key factors of structural failure were analyzed through state monitoring and port analysis. The [45°]₆ pieces improved the torsional performance of the Ti-6Al-4&#xa0;V piece by 62.9%, and the torsional performance of the [45°]₁₀ pieces was enhanced by 43.7%. More specifically, the factors influencing which torsion strengths of the [45°]₆ pieces were better than those of the [45°]₁₀ pieces were determined; these were the different types of loads borne by the fibers, matrix, and interfaces. Further, the interface strength was the most important factor. Based on the cohesive force model, a representative volume element (RVE) model of meso-mechanics was also established based on the macro-meso mechanics theory. The nonlinear unicellular structure of the SiC/Ti material was established, and the relationship between the failure index of the interface, the matrix, and the strain under different interfacial strengths was calculated. Finally, the influence of the interfacial strength on the failure was summarized. From our analysis, it was demonstrated that the interface was more likely to be damaged under the implementation of tensile loading, and the bearing performance was more stable under the application of compression loading. In addition, an increase in the interface strength can significantly delay the interface damage rate and enhance the capacity and stability of the shaft structure.</p>