Abstract: The graphene was successfully synthesized by chemical vapor deposition method using ethanol as carbon source at low hydrogen concentration and atmospheric pressure. The results of SEM, Raman, TEM and selected area electron diffraction show that the graphene has well-structure and high-quality. In order to analyze the mechanism, the experiments were designed to obtain the morphology during graphene growth. It turns out that carbon atoms originating from the thermolysis of ethanol gather and nucleate on copper surface. The initial grain develops from island domain to dendritic structure. During the process of growth, these dendrites can span the surface boundaries of copper until forming intact graphene.