Abstract: Strength variation and acoustic emission characteristics of concrete under the conditions of uniaxial cyclic loading and unloading are studied by using a 10-MN large multifunctional hydraulic servo static and dynamic triaxial test equipment and a SAEU2S acoustic emission acquisition system. Testing analysis results show that under the uniaxial cyclic loads, the ratio of concrete compressive strength to rebound values increases with the increase of a strain rate. Through linear fitting, it is found that the ratio of the concrete compressive strength to the rebound values concering the rate effect is apparent. During the uniaxial cyclic loading and unloading process of concrete, experimental studies of the acoustic emission location are carried out to reflect the position and development of concrete cracks. Then 4 deformation stages of concrete are divided; with each stage of the acoustic emission cumulative number of positioning, analysis of the damage of concrete is made; the acoustic emission cumulative fixed number of the cyclic loading and unloading process is analysed. Unloading again to the maximum stress level before a large number in history shows that the acoustic emission signal generated under such conditions does not meet the Kaiser effect; based on the relationships between the number of the acoustic emission and the time variation of the stresses, the concrete strength not only relates to the stress level, but also to the internal structure.