Abstract: The B₄C/Al composites were prepared by stirring casting method. The method of experimental analysis combined with first-principles calculations was used to explore the influence mechanism of the interfacial reaction products Al₃BC and TiB₂ on the wettability of B₄C/Al composite particles and the interfacial bonding strength. The results show that when the interface reaction product is Al₃BC, the wettability of B₄C particles has not been substantially improved, particle agglomeration still exists, and the interface bonding is poor. Excessive interface reaction makes the decomposition and loss of B₄C particles serious, resulting in insignificant strengthening effect of B₄C particles. When the interface reaction product is TiB₂ by adding Ti element, the particle wettability is significantly improved, the agglomeration of B₄C particles is significantly reduced, the interface bonding strength is higher, and the mechanical properties are significantly improved. The Al(111)/TiB₂(0001) interface adhesion work of different terminals is greater than that of Al(111)/B₄C(0001), indicating that the interface reaction product TiB₂ can improve the wettability of B₄C particles. The interface reaction product Al₃BC is very limited in improving the wettability of B₄C particles. A mixed covalent/metallic bond is formed on the interface of Al(111)/Al₃BC(0001) and Al(111)/TiB₂(0001). The chemical bonding strength on the Al(111)/TiB₂(0001) interface is greater, and the interface bonding strength is correspondingly greater.