The invention provides a noise lowering method and a noise lowering system for a vehicle and the vehicle, and relates to the field of vehicle noise lowering. The noise lowering method is used for actively conducting noise lowering on a range extender of the vehicle. The vehicle comprises the range extender, and the range extender comprises an engine module and a generator module. The noise lowering method comprises the steps that the power and rotation speed corresponding relation of the range extender and combustion parameters of the engine module are set; the phase positions of sounds generated by the engine module and the generator module are adjusted, and accordingly the sounds generated by the engine module and the generator module are the same in frequency but opposite in phase position; and the amplitudes of the sounds, opposite in phase position, of the engine module and the generator module are controlled to be mutually offset. The noise lowering system comprises the engine module and the generator module. The engine module and the generator module are set in the manner that during work, the sounds generated in the same frequency are opposite in phase position, and accordingly the amplitudes of the sounds generated by the engine module and the generator module are mutually offset. The noise lowering method and the noise lowering system for the vehicle and the vehicle solve the problems that in the prior art, due to a large number of sound isolation materials, the weight of a vehicle body is increased, consequently, the power of the vehicle is influenced, and oil consumption is increased.