Abstract: This paper analyses and discusses the indoor acoustic defects and the relevant refurbishment principle of the large and medium sized lecture halls. Based on the previous practical projects, six types of appropriate technologies for acoustic refurbishment of large and medium-sized lecture halls are summarized, and they can fulfill the requirements of good acoustic quality without sacrificing its original interior aesthetic quality. Some of those acoustic technologies have been successfully applied in the refurbishment project of the Zhonghua Hall of Yuzhou Hotel in Chongqing. Given the significantly improved reverberation time and sound distribution, the applicability and effectiveness of the above technologies are demonstrated.