A silencer comprises a main air guide tube provided with an air guide channel; the main air guide tube comprises an air inlet end and an air outlet end; both ends of an assistant air guide tube are connected with an outer wall of the main air guide tube, and the assistant air guide tube comprises a guide section and a reflux section; the guide section is provided with an air inlet, and the air inlet is communicated with the air guide channel; the reflux section is provided with an air outlet, and the air outlet is communicated with the air guide channel.