The invention relates to a novel fragrance diffusion machine which comprises a shell and a top cover, wherein an air pump is fixed inside the shell; an outer nozzle is mounted on the top cover; the upper part of the outer nozzle extends out of the top cover; the lower part of the outer nozzle extends into the shell; the outer nozzle is internally provided with a central column chamber; outer spraying holes which are communicated with the upper part of the central column chamber are formed in the side wall of the upper part of the outer nozzle; the lower part of the central column chamber is sleeved with a central plunger in a sealed manner; a fragrant liquid bottle is connected to the lower part of the central plunger; a plurality of spraying channels which are communicated with the upper part of the central column chamber and the fragrant liquid bottle are formed in the central plunger; an air inlet channel which is communicated with the air pump is formed in the central plunger; the air inlet channel is connected with a nozzle atomization structure which consists of a spraying core, a siphon backflow bucket, a siphon tube and an atomization baffle. The fragrance diffusion machine is simple and reasonable in structure, low in manufacturing cost and good in atomization effect.