Abstract: The standing wave which is formed by ultrasonic wave reflected back and forth in a solid plate was observed by dynamic photo-elastic technique. The ultrasonic stress is amplified by constructive interference, which results in the phase difference of polarized light in dynamic photo-elastic experiment greater than one cycle. The evolution process from traveling wave to standing wave was observed, and then the properties of standing waves reflected by higher order photo-elastic fringes were discussed. By measuring the ultrasonic stress quantitatively, the excitation efficiency of standing wave was evaluated. This work provides a feasible method to study high intensity ultrasound in transparent solids.