Abstract: The fracture process of concrete under compressive loading was represented by the mechanical parameters and acoustic emission (AE) characteristic parameters. The results could characterize the quantities of inner crack propagation and damage for concrete materials. The time-frequency characteristics of AE signals related with crack initiation, crack growth, microvoid collapse, and cracks coalescence were acquired based on the transient analysis using wavelet transform method. The rise time and frequencies of AE signals, which were associated with crack initiation, crack growth, microvoid collapse, and cracks coalescence, systematically increased and decreased, respectively. The experimental results are in a good agreement with the strain energy release theory.