Abstract: It is generally believed that acoustially insulated buildings emerged at the begining of the twentieth century. Through historical documents we show that sound insulated buildings appeared at the beginning of the Ming Dynasty in China. According to the accounts in the Biography of Yao Guangxiao in the History of the Ming Dynasty and other works, it was Yao Guangxiao(1335－1418) who first discovered the sound-absorbing effect of porous wall, and secretly built an underground sound insulated room in 1398. At the end of the Ming Dynastry, Fang Yizhi(1611－1671) summarized the principles of sound absorption of porous wall in the Wu Li Xiao Shi and first used the word　′sound insulation′. From then on, the techology of sound insulated buildings was generally known throughout China.