<p>Cemented carbides are widely used in cutting tools, wear-resistant parts and other fields. In order to further improve the mechanical properties, additives are usually added to cemented carbides. The interface bonding strength of additives with WC and Co phases will affect the crack propagation and have an important influence on the mechanical properties of cemented carbides. The gradient of electron work function (EWF) at the interface of WC/additive and Co/additive were obtained by atomic force microscope in this paper. According to the numerical relationship between the gradient of EWF and the interface bonding strength, the interface bonding strength of different additives and cemented carbide were qualitatively studied. The results show that in the interface of WC/additives, the interface bonding strength of WC/VC is the largest, followed by WC/TiC and WC/ZrO₂. In the interface of Co/additives, the interface bonding strength of Co/VC is the largest too, followed by Co/ZrO₂ and Co/TiC, which verified the feasibility of this method in the field of cemented carbide.</p>