Abstract: This paper discusses decay of standing waves in a small room based on the formation of reverberation time equation. Fluctuations in the reverberation time curve at low frequencies are interpreted as a consequence of standing waves. Methods for avoiding such fluctuations are introduced with the acoustic design of the studio of Huayi Audio-Video Co. Ltd. of Nanjing as an example. The measurement results show that a flat reverberation time curve and quiet circumstance have been achieved in the design.