The environment of some slopes consists of a set of stone blocks placed in the soil, which are called stone-mixed slopes. In these slopes, part of the potential slip surface is located in the soil environment and the other part passes through the contact point between the stone blocks and the soil. Therefore, the shear quantities between the stone blocks and the soil have a significant effect on the stability of the aforementioned slopes. So far, this issue has not been investigated quantitatively by researchers. In this paper, the effect of the adhesion coefficient and the friction angle of the contact surface between the soil and the stone blocks on the stability of the stone-mixed slope is investigated by sensitivity analysis. For this purpose, the finite element numerical method and the construction of 146 theoretical models have been used. The results of this research show that, in general, the sensitivity of the slope to the friction angle between the soil and the block is greater than the adhesion coefficient between these units. Also, changes in the above quantities can change the safety factor of a stone mix slope by up to 50%. Therefore, for analyzing the stability of the aforementioned slopes, the aforementioned quantities must be given special attention.