Abstract: Flow-induced acoustic resonance in closed side branch is a flow-acoustic coupling phenomenon caused by the interaction of flow and acoustic fields in special structure. The flow-induced acoustic resonance characteristic experiments were carried out on cylindrical closed side branch to study the influences of the velocity in main pipe and the height of the side branch on acoustic resonance. The range of occurrence and characteristics of pressure pulsation were analyzed. Five heights of side branches (H/d=6, 8, 10, 12, 14) are experimentally studied and the Reynolds number in the experiment is 3.24×10⁴-2.89×10⁵ while the Mach number is 0.029-0.26. It is found that the resonance frequency shows a lock-in phenomenon with the increase of velocity. As the height of the side branch increasing, the acoustic mode frequency decreases while the amplitude of the acoustic pressure shows no significant changes as the wall of the side branch approximately equals to rigid wall. In the considered structure, the acoustic resonance occurs when Strouhal number is in the range of 0.2-0.55.