The nano-cooper powder and graphene are mixed by the way of mechanical wet ball-milling. Then the graphene/cooper (G/Cu) composite materials is prepared by the Spark Plasma Sintering method(SPS). The microstructure and organization structure of graphene and cooper power are analyzed by means of SEM, XRD and other test methods to explore the relationship between the variation of graphene and cooper power and the ball-milling process. It has found that when the ball-milling time increased to 8h, the grapnene nanoplates have a better combination and distribution on cooper substrate. The improvement of performance is relatively best. The tensile yield strength of the G/Cu composite is 183MPa, increased by 52.5%compared with Cu matrix; the compres yield strength is improve more nearly 1.4 times from 150MPa to 365Mpa; the hardness is also increased to 135HV; the conductivity IACS of the composites reaches 65.5%. The comprehensive performance increased significantly.