Abstract: The AE technique is a very functional and valid technique applied on rolling element bearings diagnosis and examination. Based on the vibration analysis of AE signals under varying load and rotating speed, the patterns of damage vibration of rolling element bearings under varying load and rotating speed were researched. The characteristic parameters of AE which were defined based on vibration analysis under varying load, rotating speed and damage type were also studied. The results provided a new technique for security running, condition monitoring, and fault diagnosis of rolling element bearings.