In the reinforcement and repairmen of existing stone structures by ultra-high performance concrete (UHPC), the excellent bonding performance between UHPC and stone is the key to ensure the reinforcement effect. Therefore, in order to explore the interface bonding performance between UHPC and stone, the effects of different interface treatment methods were investigated by splitting tensile test and double L-shaped shear test. The results show that the failure modes of the interface between UHPC and stone are mainly divided into three types. The interface bonding strength is the largest when mode C failure (stone UHPC failure) occurs. The interface groove treatment method significantly improves the interface bonding strength and interface shear stiffness of UHPC-stone specimens. Simultaneously, the interface groove treatment method effectively improves the ductility of specimens while changing the failure mode. When the groove depth is 20 mm, specimens show better interface bonding performance. In addition, the shear load-displacement curve of specimen includes the pre-slip stage and the post-slip stage, and the chisel specimen does not experience plastic deformation in the post-slip stage. Under the same interface treatment method, the interface shear strength between UHPC and stone is positively correlated with the interface splitting tensile strength.