• The diffusion behavior of the elements at the interface is investigated. • The diffusion reactions of the interface are analyzed. • The growth kinetics of the interfacial compound are analyzed. • The interfacial microstructure evolution model of BAl88Si/Cu are established. In this study, the growth of the intermetallic compounds (IMCs) at the BAl88Si/Cu interface was analyzed and its growth kinetics was investigated. The results reveal that Cu 3 Al, Cu 9 Al 4 , Cu 3 Al 2 and CuAl, four-layer IMCs are formed at the interface due to the interdiffusion of copper elements and aluminum elements. The thickness of the IMCs increases with increasing temperature and holding time, the transition from Cu 3 Al 2 to Cu 9 Al 4 is also observed at 893 K. The activation energies of the Cu 3 Al, Cu 9 Al 4 and total IMCs layers are obtained from the Arrhenius equation and are 127.10 kJ/mol, 189.68 kJ/mol and 184.93 kJ/mol, respectively, which provide a reference for assessing the ease of growth of IMCs.