Abstract: Ultrasound had become a ubiquitous technological process in a large variety of scientific disciplines.In recent years, biological effect of ultrasound had been applied in food process, and consequently an overview of work reported was provided on this topic. The review mainly provides a discussion of the influence of ultrasound on microbial fermentations and enzymology. At last, some suggestions on the application of biological effect of ultrasound in food processing in the future were given. Proper ultrasonic effect on fermentation process could shorten the fermentation time, improve the reaction conditions, and improve the product quality and yield.