Niobium carbide (NbC) reinforced metal matrix composite (MMC) coatings have been widely applied for surface strengthening, and the precipitation of granular primary NbC may be a feasible way to improve the wear resistance of coating. In this work, MgAl2O4 was selected to promote the precipitation of granular primary NbC, and a combination of experimental observations and first-principles modelling were carried out to investigate it. The calculation results show that, misfit between MgAl2O4 and NbC is 8.7%, which indicates that the MgAl2O4 nucleating effecting on NbC is structurally potent. In order to eliminate the interference combination between different elements, the MgAl2O4 (1 1 1)/NbC (1 1 1) interface overlaps were selected, and four different element matches are designed: O(Mg)Nb, Al(Mg)Nb, Al(Mg)C and Mg(O)C. From the interfacial adhesion work and interfacial energy, the stability order of the four models can be found: O(Mg)Nb > Al(Mg)C > Al(Mg) Nb > Mg(O)C. Moreover, mixture bonding of metal bonds, ionic bonds and covalent bonds are formed at the interface of O(Mg)Nb, Al(Mg)Nb, Al(Mg)C and Mg(O)C. From the experimental results, core-shell primary NbC carbides can be observed in M-1 (0.5 wt% AlMg alloy powder) coating and the core of carbide is identified to be MgAl2O4. Besides, the wear loss of M-1 coating is decreased, compared to M-0 coating.