The paper presents theoretical and experimental studies to investigate how one can control and suppress cascade flutter through an acoustic excitation. The model considered herein is a three-dimensional linear cascade of flat plates oscillating in a low speed flow between parallel walls. An actuator consisting of loudspeakers is set on a wind tunnel wall at the blades tip side, and generates sound waves with the same frequency of the blade vibration. To determine the most suppressive condition, the dependence of the suppression effect on the width, location of actuator surface and phase difference between the blades and actuator is investigated. Experimental results show that the loudspeakers can work most effectively when the centerline of the actuator surface is located at three-quarters chord point from the leading edge of blades. Furthermore an 8% increase in the critical flutter velocity of 5.3 Hz coupled bending-torsion flutter is obtained.