In this paper, the sample of Ti/Ni multilayered composites fabricated by 5 cycles ARB were treated with different heat treatment. The microstructure, interface structure and the thickness of Ti/Ni interface diffusion layer were analyzed by the optical microscope(OM) and scanning electron microscopy (SEM) analysis technology, combined with the dynamic theory to study the diffusion behavior of Ti/Ni interface. The results show that the Ti/Ni interface did not diffusion during accumulative roll bonding processes. After heat treatment with(550 ℃-750 ℃)×(0.5 h-8 h), the Ti/Ni interface occurred diffusion, the thickness of diffusion layer was power function within the experimental time, the thickness is exponential function relation with temperature. With the increase of heat treatment temperature, the growth of Ti - Ni diffusion layer was controlled by the body diffusion under 650 ℃ gradually transformed into grain boundary diffusion controlled. Through the calculation and verification we can get the dynamics equation of reaction layer growth of Ti/Ni interface of Ti/Ni multi-layer structure composite material produced by 5 cycles accumulative roll bonding is:y=1.7043*104*exp(-78202/RT) *t1.2009-0.0008T .