Abstract: The new theoretic development on acoustooptic interaction is introduced. Adopting the tentation of raster，the acoustooptic interaction in isotropic medium is discussed, and the formula of diffractive efficiency for the diffractive beam is deduced. A new experiment equipment on acoustooptic interaction is developed. By means of a linear array CCD lightintensity distribution measuring system, via the variation of the frequency and the power of ultrasonic wave, the direction control and the intensity modulation for the laser beam can be carried out. The relation curve between acoustooptic deflexion and modulation measurement is given. The experimental result shows that as the power of ultrasonic wave is fixed, and the relation curve of the diffractive lightintensity relative to zeroorder diffractive light and ultrasonic frequency is measured, not only the sound velocity can be calculated,but also the bandwidth and the centric frequency of an acoustooptic element can be confirmed under Bragg diffraction.