The measurements of the information on the carrier frequency can be realized by the acoustooptic deflection effects. However, when the multiradio frequency signals are simultaneously input to the acoustooptic deflector, the intermodulation between the signals will be generated in the Bragg regime. It causes great difficulties to signal detecting, especially interference from the thirdorder intermodulation is particularly serious. In response to the intermodulation interference coming from the acoustooptic diffraction, the conditions of generating intermodulation, diffraction distribution, and frequency spectrum are discussed on the basis of the principle of the interaction of the acoustooptic diffraction. Through theoretical analysis, the methods and measures by which the phenomenon of the intermodulation can be reduced are proposed. In order to verify the degree of intermodulation interference in the detection of multifrequency signals, a test system is constructed. By way of experimental analysis, the conclusion that the intermodulation interferences can be reduced effectively by controlling drive power of radio frequency (RF) properly to ensure that acoustooptic deflector works in linear regions is drawn, when diffraction efficiency in the effective bandwidth of acoustooptic deflector is fixed.