Cold-rolled Ti/Al laminated composites were annealed at 525-625 °C for 0-128 h, and the interfacial microstructure evolution was investigated. The results indicate that only the TiAl₃ phase was formed at the Ti/Al interface; most of TiAl₃ grains were fine equiaxed with average sizes ranging from hundreds of nanometers to several microns and the TiAl₃ grain size increased with increasing annealing time and/or temperature, but the effect of annealing temperature on the TiAl₃ grain size was far greater than that of annealing time. The growth of the TiAl₃ phase consisted of two stages. The initial stage was governed by chemical reaction with a reaction activation energy of 195.75 kJ/mol, and the reaction rate constant of the TiAl₃ phase was larger as the Ti/Al interface was bonded with fresh surfaces. At the second stage, the growth was governed by diffusion, the diffusion activation energy was 33.69 kJ/mol, and the diffusion growth rate constant of the TiAl₃ phase was mainly determined by the grain boundary diffusion owing to the smaller TiAl₃ grain size.