The ability to control pattern formation of materials and a better understanding of the processes are of both technological and scientific importance.However, pattern formation involves complicated non-equilibrium processes that are still poorly understood in theory and difficult to be controlled in real systems.Here we describes a general approach that allows the morphologies of graphene flakes (GFs) grown on liquid copper surface to be precisely controlled from compact to dendritic using CH4-chemical vapor deposition (CVD) method by modulating the flow rate ratio between inert gas and H2 carrier gas.