In this study,a steep-slope bridge pile foundation was taken as the research object,and a finite element model of the pile foundation under the action of inclined loads was established. The influences of load sequence, load type, elastic modulus of pile body, and main mechanical characteristics of soil on the horizontal bearing characteristics of pile foundation of a steep-slope bridge were analyzed. The results show that the horizontal displacement of the pile top and the internal force of the pile foundation increase when the vertical load is applied. The mechanism of vertical load acting on the horizontal displacement of pile top should consider the effect of "P-?" and the effect of lateral soil pressure around the pile. The three-stage characteristics of the relationship between the load on the slope top and the maximum bending moment of the pile body are proposed. The exponential variation rule of improving soil cohesion，internal friction angle, and elastic modulus to reduce horizontal displacement of reduce is revealed. The results can provide a reference for the design and construction of steep slope bridges in mountainous areas.