With the fast development in Intemet and communication technologies,vehicles that often quickly move in cities or suburbs,have the strong ability of computation and communication.Then many researchers called vehicles as computers with four wheels or big phones in Internet of Vehicles (IOV).IOV is emerging as an important part of the smart city being proposed and developed around the world.IOV is a complex integrated network system that interconnects people within and around vehicles,intelligent systems on board vehicles,and various cyber-physical systems in urban environments.