Vibration-driven locomotion systems offer potential advantages for robots operating in complex environments, but their performance on inclined surfaces requires detailed investigation. This paper studies the influence of the supporting surface inclination angle (α) and the imbalanced rotor inclination angle (β) on the locomotion characteristics of a vibration-driven capsule robot. A mathematical model incorporating dry anisotropic friction is developed, and the differential equations are solved numerically using Wolfram Mathematica software, employing the “StiffnessSwitching” method. Results demonstrate that the surface inclination angle significantly impacts motion; a critical climbing angle (about 30°) exists, beyond which forward motion ceases. Downhill motion enhances displacement and velocity. The rotor angle strongly affects performance on a horizontal surface: optimal locomotion (maximal displacement and peak velocity) occurs at β = 0°, while performance degrades as the angle increases, halting completely at β = 90°. This study provides quantitative insights into these dependencies, which are valuable for the design optimization and control of vibration-driven robots intended for navigating varied terrains.