The lattice misfit between Y 2 O 3 and TiC low index faces was calculated by the Bramfitt two-dimensional lattice misfit theory in this work. The interface electronic structure, adhesive work and interfacial energy of Y 2 O 3 (111)/TiC(110) interfaces were calculated by the first principles method. The interfacial bonding characters were analyzed by the interface charge density, electron density difference and mulliken populations. The microstructure of the hypereutectic Fe-Cr-C-Ti-Y 2 O 3 coating was observed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The calculational results show that, the lattice misfit of Y 2 O 3 (111)/TiC(110) interface is 8.6%, which meets that Y 2 O 3 acts as 2 medium effective heterogeneous nucleus of TiC. Four interface models have been constructed according to the surficial termination situations and interfacial atomic stacking modes, in which O-TiC2 interface is most stable. Its interface adhesive workis the largest (6.07J/m 2 ) and its interfacial energy is the smallest (-1.22J/m 2 ). And its interfacial bonding is a mixture of polar covalent, metallic and electrovalent bonds, which proves that Y 2 O 3 and TiC can form a stable interface. The experimental results show that, Y 2 O 3 particle exists in the core of the flower-like TiC particle in the hypereutectic Fe-Cr-C-Ti-Y 2 O 3 coating and they are combined tightly, which proves that Y 2 O 3 can act as the heterogeneous nucleus of TiC.