The Au/Au(100) epitaxial growth with energetic deposition was simulated by using kinetic Monte Carlo method.The influences of energetic atoms on morphology and atomistic processes in the early stage of film growth were investigated.The reentrant layer-by-layer growth was observed in the temperature range of 450K to 100K.We found the energetic atoms can promote the nucleation and island growth in the early stages of film growth and enhance the smoothness of film surface at temperatures of film growth in 3-dimensional mode and in quasi-two-dimensional mode.The atomistic mechanism that promotes the nucleation and island growth and enhances the smoothness of film surface is discussed.