Abstract: Acoustic metamaterials, artificial structures with structural units much smaller than the operating wavelength and possessing unusual properties, were first reported in 2000, when they were called locally resonant sonic materials. Like electromagnetic metamaterials, acoustic metamaterials have also attracted much attention in recent years. In this article, the main advances in the research of acoustic metamaterials are reviewed, including the realization of negative acoustic parameters by introducing local resonances in the medium, and the determination of various acoustic parameters for metamaterials without local resonances. Finally, an overview is given of the prospects for potential applications.