Abstract: Acoustic emission technique(AET) is a progressive mature nondestructive testing method which began in 1960s. The AET provide a new approach to the testing and failure diagnosis of bearing because of its characteristics of high sensitivity, wide frequency response range, large quantity and dynamic detection. And it is also the bearing fault diagnosis area of research focus in recent years. The application of acoustic emission technique in the world and China in the rolling and sliding bearings detection was reviewed. By analyzing the acoustic emission detection of bearing, the future research direction was concluded, and it indicated that acoustic emission detection of bearing failure was a powerful supplementary tool for vibration testing, especially in the bearing failure of low speed and better early detection role.