Abstract: The building structure in the southwest of China crosses into the mountain areas. Many pile foundations are located in slope terrain grounds that the overburden is gravel soil. The pile-soil interaction caused by pile deformation can generate soil horizontal resistance. If the soil resistance is too small to prevent slope deformation, the slope can be unstable and destroyed. However, the existing codes do not provide the methods to calculate the soil resistance on slope ground. This paper presents four piles that are in gravel soil under in-situ lateral loading tests on terrain with 30°slope angle. Based on the measured data, the relationship between deflection and soil resistance for the four piles is compared. The results of the above analyses are used to establish the mode of horizontal resistance distribution for gravel soil slope ground in elastic and plastic phases.