In the manufacturing of micro/nanocomposite materials, micro/nanoparticles need to be dispersed evenly into the base materials. However, due to their high surface-to-volume ratio and high surface energy, the micro/nanoparticles tend to agglomerate and cluster together. Ultrasonic cavitation is effective to disperse micro/nanoparticles. However, works on correlating the cavitation parameters with the micro/nanoparticle dispersion are limited. This paper presents a real-time acoustic monitoring method based on cavitation noises to monitor the micro/nanoparticle dispersion status. In this paper, two types of cavitation noise power indices computed based on the raw cavitation noise signals are used to monitor the cavitation status. Both off-line and on-line steady state detection algorithms are developed. These algorithms can be used to determine the critical process parameters including the power of the ultrasonic sound and the dispersion time. Extensive experiments have been conducted to illustrate the effectiveness of the developed methods.