The present invention belongs to the field of chemical fluid mechanical technology, and relates to one kind of hydraulic cavitating disinfector. The disinfector consists of mainly pump, pipeline, orifice plate, flange, material tank, valve, pressure meter, etc. The present invention features that the throttling effect of the orifice plate is utilized to produce hydraulic cavitation and the instantaneous high temperature and high pressure produced during cavitating is utilized in disinfecting fluid material. The disinfector features high efficiency, convenient operation, instantaneous disinfection, local high temperature and integral normal temperature, etc. and can avoid the damage and overheat decomposition of effective components in the liquid material. The present invention is suitable widely for disinfection of water, milk, fruit juice, and other beverage, food and nutriment.