The influence of ultrasonic treatment at various stages of modification of ZSM-5 zeolite with magnesium compounds has been studied to obtain a nanosized zeolite and increase the dispersion of the active element. It has been found that the use of sonication at various stages of magnesium incorporation into the zeolite structure alters the texture and acid properties of the catalyst. Using temperature-programmed ammonia desorption and diffuse reflectance infrared spectroscopy, it has been shown that the sonication leads to an increase in the proportion of Bronsted acid sites of medium strength.