The bearing capacity of power pile foundations on fractured rock slopes is influenced by multiple factors such as the rock mass structure, geological conditions, and external loads. The complex mechanical behavior increases the difficulty and uncertainty in pile foundation design. This study investigates the bearing characteristics and key influencing factors of power pile foundations in fractured rock slopes through numerical simulation and parameter sensitivity analysis. First, a pile-rock interaction model was established based on the ubiquitous-joint rock mass constitutive model, and the displacement response and failure modes of the pile under vertical and horizontal loads are analyzed. It is shown that, the bearing capacity of the pile is significantly affected by the embedment depth and slope inclination angle, with the latter being the dominant parameter controlling pile performance—particularly for horizontal loading conditions. Optimization of the embedment depth can enhance the anti-sliding capacity of the pile. The findings provide a theoretical basis for the design and reinforcement of power pile foundations in fractured rock slopes, offering valuable insights for improving the safety and cost-effectiveness of pile engineering.