Abstract: This paper focuses on the theory, setup, and experiment of a visualization system for surface acoustic wave (SAW) distribution based on knife-edge laser probe. The surface micro-bend caused by the SAW leads to variations of incident light to an optical detector. The converted electrical signal is down-converted to intermediate frequency for detection, and the output signals including both the amplitude and phase are fed to the high-speed data-logger. Data acquisition of 2 620(x)×410(y) points in 20 min is realized, then image can be formed from the data.