The invention relates to a range hood. Brand new design is adopted for a mechanical structure, a working mode, a purification mode, a 
flue structure, a circulation mode and a 
control mode of an existing range hood. Efficiency, energy-saving performance and cleaning performance are higher. The range hood comprises a range hood body 1, a straight-through gas duct and a hemispherical and double-arc 
plasma electrostatic blade 7, a valve capable of being opened and closed, an indoor gas outlet 8 capable of being linked, a venturi principle gas inlet and gas outlet 
flue 9, an 
exhaust gas recirculation pipeline 11, an EGR control valve 12, a venturi tube type EGR 
system 13, an 
exhaust gas circulating 
system 14 with a 
machine turbochargning device and a turbocharging device, a flow guide vane 15 with an adjustable section, an 
exhaust pipe 16 allowing a hole in an exhaust tube for exhausting circulation of the range hood, a 4-2-1 exhaust tube 17, a single-
turbine double-vortex tube 18 and a 
smoke machine shell cavity integrated type pipeline 19, wherein a 
centrifugal fan 2 is replaced with a movable vane adjustable axial flow fan and a 
mixed flow (oblique flow) booster fan; the fans can also be connected in parallel and connected in series, and the rotating speed can be adjusted; an 
impeller adopts three-element flow blade design 4; guide grooves 5 and a 
fan blade fairing 6 are arrangedon the 
impeller; and a sawtooth shape 10 is adopted at the 
tail edge of the contraction section of an exhaust port.