Using X-ray diffraction line profile analysis (XRDLPA), the recrystallization behaviors of TiB 2 /6351Al and 6351Al deformation layers introduced by shot peening (SP) have been investigated during isothermal annealing. The recrystallization activation energies of both materials were obtained by regression analysis. The results showed that the recrystallization activation energy of the composite is slightly higher than the alloy's one. Reinforcements had two effects on the recrystallization behavior: (1) promoting recrystallization at the early stage of annealing and (2) impeding the movements of grain and subgrain boundaries. The combination of the two opposite effects together with the lower volume of reinforcements and their inhomogeneous distributions weakened the influence of reinforcements on the recrystallization activation energy.