According to the lateral bearing characteristics of bridge piles in sloping ground, the pile-soil interaction model considering the slope effect and the differential equation of flexural deformation was established. Based on the m method and transfer matrix method, the transfer matrix solution of pile internal force and displacement analysis was derived. The proportional coefficient of clay and sand slope foundation were measured by model tests. The relationship between the proportional coefficient of slope foundation and slope angles was obtained by nonlinear fitting, and then the rationality of theoretical solutions was verified by the model test. Based on an engineering example, the influence of slopes and horizontal loads on the internal force and deformation of piles in the sloping ground were analyzed. The results show that: the proportional coefficient of sloping ground decreases nonlinearly with the increase of horizontal displacement of the pile at the pile-soil interface. The proportion coefficients of clay and sand sloping grounds decrease with the increase of slope angles. The horizontal displacement of the pile top and the maximum bending moment of the pile body increase with the increase of slope angles and horizontal loads. When the slope angle increases from 0° to 60°, the horizontal displacement of the pile top increases by about 86.4%, the maximum bending moment of the pile body increases by about 4.6%, and the position of the maximum bending moment move down by about 2.0 m. When the horizontal load is increased by 50 kN, the horizontal displacement is increased by 48.5% and the maximum bending moment is increased by 41.6% on average.