New technology is offered for measuring and control of light intensity. In the proposed method the phenomenon of acoustical activity and Bragg light diffraction on hypersonic waves in ferroelectric crystal LiNbO3 is used. Control of light intensity can be realized by transference of crystal or by modification of generator frequency by which the transverse acoustic wave is excited. The change of light intensity is provided electronically, fluently and with high accuracy. Using previously the standard calibration, it is possible to measure and change the light intensity to the necessary value.