In this paper, the solid phase diffusion reaction behavior between Ti and Al is characterized from 520 to 630℃ at different annealing time with titanium and aluminum being superfluous. In the samples annealed up to 46h, only intermeallic TiAl3 phase forms and grows at the Ti/Al interface. It was found that the growth rate of TiAl3 towards TiAl3/Al interface is more rapid than that towards the Ti/TiAl3 interface. Additionally, the solid-state diffusion reaction kinetic equation of TiAl3 is successfully established in the present work. The reaction activation energy of Ti/Al is calculated to be 170.1 kJ·mol-1 and dynamic index n is 0.5. Hence, the growth of TiAl3 is controlled by normal parabolic law with annealing time. Ti/Al powder compact is employed as experiment material to identify the proposed reaction kinetic equation for the growth of TiAl3. It is suggested that no extra aluminum was found in the specimen annealed at 590℃/4.5h, and the aluminum is still found at 590℃/3.5h, indicating that is in a good agreement with the developed solid-phase diffusion reaction equation.