Abstract: Double-leaf wall structure with its favorable sound insulation is widely used in variety building envelopes． Once coincidence superposition which occurs within some frequency ranges will severely impair the sound insulation of this structure． For the purpose to eliminate the effects of coincidence superposition，statistical energy analysis ( SEA) theory is adopted in predicting sound insulation of the specific double-leaf wall． The results indicate that structural coincidence effect can be predicted accurately by SEA model，therefore，the suitable double-leaf wall structures which attenuate coincidence effect are obtained，that is，the influence of the coincidence effect on the sound insulation will be abated by altering the sequence，density and thickness of each material layer of a doublelayer wall． For instance，the thin panel towards sound source can effectively reduce coincidence effect which generates sound insulation deterioration of the structure and the coincidence effects at low and high frequency ranges are attenuated substantially whilst both the walls of double-leaf wall are light-weight panels． 

Key words: double-leaf wall structure, superposition of coincidence effect, depth of coincidence dip, sound insulation prediction