The processes of multilayer thin Cu films grown on Cu (100) surfaces at elevated temperature(250-400 K)are simulated by mean of kinetic Monte Carlo (KMC) method,where the realistic growth model and physical parameters are used.The effects of small island (dimer and trimer) diffusion,edge diffusion along the islands,exchange of the adatom with an atom in the existing island,as well as mass transport between interlayers are included in the simulation model.Emphasis is placed on revealing the influence of the Ehrlich-Schwoebel (ES) barrier on growth mode and morphology during multilayer thin film growth.We present numerical evidence that the ES barrier does exist for the Cu/Cu(100) system and an ES barrier EB＞0.125 eV is estimated from a comparison of the KMC simulation with the realistic experimental images.The transitions of growth modes with growth conditions and the influence of exchange barrier on growth mode are also investigated.