Many electric transmission tower footings built on the slopes in mountainous area, it is necessary to study the additional stress distribution of slope foundation. In this paper, model tests and numerical experiments are used to research the influence on stress distribution and diffusion regularity of the additional slope foundation induced by the distance from the top of the slope. Results of the model test show that the distance from the top of the slope has a great impact on the additional stress in soil. Additional stress increases with the increase of the distance from the top of slope and has obvious asymmetry on both sides of the foundation when it is less than the safe distance. Additional stress gradually stabilized, close to the level ground state when the distance from the top of slope is more than the safe distance. When the distance from the top of slope is 0.3 m, additional stress in shallow soil is close to 50% of the plane foundation condition, the influence of additional stress in soil slope is very significant; and traditional additional stress calculation method is not applicable to slope foundation. In the small distance from the top of slope conditions, the additional stress is small; but the corresponding ground deformation is greater; it is proved that the traditional layerwise summation method is not suitable to calculate the deformation of the foundation in the slope. Otherwise, it will affect the safety of engineering. In the case of foundation stability meet the requirements, it is recommended that the minimum distance from the top of slope is not less than the safe distance.