Abstract: Acoustic emission(AE) technology was used during tensile tests to detect in real time the tensile behavior and damage evolution of the Al2O3/4043Al-Alloy system. The SDAEA signal analysis system was applied to analyze the amplitude, energy, ringing-counts, impacting speed rate, waveforms and FFT of AE data. The emergence and evolution of microcracks with Al2O3 coating was recognized during tensile process, the in-plane tensile strength and the cohesive strength of Al2O3 coating were also introduced by analyzing the regularity of AE signals against time.