An extensive first-principles database of alloying behavior of 37 elements in the Al(111)/TiB 2 (0001) interface is presented. The interfacial ability is systematically compared via the formation energy, interface energy, and work of adhesion. The thermodynamically most stable interface with the Ti terminal and center stacking sequence is selected to analyze the alloying behavior. According to the interfacial stability and wettability, an alloying trend map containing 11 excellent elements (Mg, Ca, Ag, Ce, Au, Pd, Y, Sc, Pt, Hf, and Zr) is obtained. These elements can effectively improve the dispersion of TiB 2 particles in Al-based composites by promoting the formation of the Al/TiB 2 interface and improving the interfacial wettability. Based on the number of valence electrons in the d orbital, these alloying elements can be divided into zero-d (Mg and Ca), low-d (Sc, Y, Zr, Ce, and Hf), and high-d (Pd, Ag, Pt, and Au) elements. In combination with the electronic structure of the alloying interfaces, the alloying mechanisms are discussed depending on the hybridization between Al and alloying atoms. Generally, our calculation guides the interface alloying strategy to enhance the particle dispersion in the metal matrix composite and provides a fundamental explanation for the related interfacial mechanisms.