This paper detected the variation of sodium chloride (NaCl) in egg white during the salting process of duck eggs and found that the viscosity of egg white had a natable effect on the velocity of NaCl penetrating into egg white. Taking advantage of the characteristics of ultrasonic wave which can decrease the viscosity of egg white,ultrasonic wave technology was applied in salting duck eggs with the result of promoting the osmosis and diffusion of NaCl and shortenting the salting period. This result preliminarily proclaimed the mechanism that ultrasonic wave promoted duck egg salting and provided important theoretical basis for the application of ultrasonic wave to the production of salted duck eggs.