The invention relates to the field of chemical reaction technical devices, and relates to an ultrasonic-assisted enhanced turbulence cyclone reactor for preparing fine particles. The reactor comprisesa main body, and the main body is provided with a feeding channel used for providing high-speed jet flow for a reaction, a reaction cavity enabling the high-speed jet flow to form vortex flow and used as a particle reaction place, a contraction section cavity enabling particles to be coalesced and crushed and a discharging channel used for outputting fine particles, which are communicated with each other in sequence, and the initial jet flow flowing direction of the discharging end of the feeding channel is perpendicular to the central axis of the reaction cavity in different planes and is tangent to the inner wall of the reaction cavity. The ultrasonic-assisted enhanced turbulence cyclone reactor for quickly and controllably preparing the fine particles has the advantages of simple structure, safety in operation, quick reaction and low energy consumption, and can meet the industrial standard and requirements of fine particle powder materials at the same time.