We have studied the global existence of weak solutions for compressible Navier-Stokes/Allen-Cahn (NSAC) systems with slip boundary conditions, which describe the flow of immiscible two-phase flow with diffusion interfaces. Under the conditions of limited initial energy and adiabatic constant γ > 2, the global existence of weak solutions for initial boundary value problems with Navier-slip boundary conditions is proved using the Faedo-Galerkin approximation and a weak convergence limit.