Diffusion and solution phenomena of heterogeneous atomics in binary metallic liquid/solid interface has a very wide range of applications in materials engineering, the structures and properties of the diffusion-solution zone play an important influence on the final product quality. Therefore, the study of the formation mechanism of the new intermetallic phases in interface, and prediction and control of the structure of the diffusion-solution zone have very important theoretical and practical significance. According to the heat treatment experimental results of Al/Fe, Al/Ni, Al/Ti liquid/solid interfaces, the formation mechanism of intermetallic compounds in binary metallic liquid/solid interface was analyzed. Moreover, the cohesive energy and formation heat of stable intermetallic compounds at room temperature in Al-Fe, Al-Ni, and Al-Ti binary system were calculated based on the empirical electron theory of solids and molecules, and the prediction criterion of new phase's formation order in interface was given. Predicted results of new phase's formation order in Al/Fe, Al/Ni, and Al/Ti liquid/solid interfaces based on the criterion agree well with the experimental results.