The interaction between high power ion beam and the double-layer target system consisting of Ti film and Al substrate was simulated by TRIM Code. The evolution of energy distribution in the double-layer target irradiated by high power ion beam (HPIB) was obtained. Using the deposited energy in the target as the thermal source term in the nonlinear thermal conduction equations, finite differential method was used to solve the equations. And one-dimensional spatial and temporal evolution of the temperature of the Ti/Al double-layer target irradiated by HPIB during a pulse was obtained. The effect of the ion beam current density on the phase state of the film substrate interface was analyzed. The results show that both Ti and Al are melted at the interface when the ion beam current density is between 100 and 200 A·cm-2.