Giant enhancement of light emission and laser action have been demonstrated in the new composites consisting of SnO2 nanowires and graphene nanoflakes (GNFs). Quite surprisingly, even the band edge emission is undetectable in the pristine SnO2 nanowires, but it can be greatly enhanced and the laser action can be achieved in GNFs/SnO2 nanowires composites. The underlying mechanism is attributed to the resonant coupling between the surface plasmon of graphene induced by the surface corrugation and the band edge transition of SnO2 nanowires. Our approach shown here not only paves an excellent alternative for the generation of high-efficiency semiconductor optoelectronic devices, but also opens up a new avenue for the application of two-dimensional graphene crystal.