Abstract: An ultrasonic atomizing nozzle with a resonant frequency of 18 kHz has been designed. The finite element analysis software was used to analyze the modal analysis and the harmonic response. Through the analysis of the first ten modes of the ultrasonic nozzles, the resonant frequency of the longitudinal vibration was 18 290 Hz. Through the harmonic response analysis, the frequency longitudinal vibration displacement curve of the atomized disk, flange plate and the nozzle front end face were obtained. Work stress diagram and the total deformation map at 18 290 Hz frequency were also obtained. The maximum amplitude of the nozzle was 4.6×10^-6 m at the atomized disk and the amplitude was 5.5×10^-9 m at the flange. Compared with the amplitude of the atomized disk, the amplitude of flange was very small. The stress and deformation of the horn at the arc transition reached the maximum. The results show that the longitudinal resonance frequency of 18 290 Hz was very close to the theoretical value of 18 kHz. It proves that the design was reasonable and correct.