The invention discloses an intermediate-frequency ultrasonic atomizer. The intermediate-frequency ultrasonic atomizer comprises piezoelectric ceramics, an upper end insulating ring, a metallic end cap, a central metal ring, a negative wire, a positive wire, a lower end metal ring, a liquid inlet, a lower end insulating ring and silver, wherein the metallic end cap is in the shape of a cycloid curve, the polarization direction of the piezoelectric ceramics is radial thickness direction, the atomization amount is high, the reliability is high, and the service life is long; the working frequency of the intermediate-frequency ultrasonic atomizer can reach to 300-500 KHz. The intermediate-frequency ultrasonic atomizer can obtain smaller fog drops without destroying the chemical structure of nutrient solution, and overcomes the defects that the chemical structure of the nutrient solution is destroyed by a high-frequency ultrasonic atomizer and larger fog drops are produced by a low-frequency ultrasonic atomizer. The intermediate-frequency ultrasonic atomizer can be applied to the field of atomization cultivation.