Laser shock peening (LSP) is an advanced surface modification technology that can harden metallic materials by using plasma shock waves. It has significant technical advantages and has important application value in various fields like the aerospace, defense and military. In order to realize the large-scale industrial production of LSP, it is necessary to strengthen on-line monitoring of its working status. Acoustic emission (AE) is a dynamic non-destructive technique to evaluate the material performance change in real-time, which overcomes many shortcomings of traditional non-destructive testing methods and has been successfully applied to on-line monitoring of LSP. Generally the signal and characteristic parameters of AE are affected by sensor position, which is inconvenient to evaluate the quality of LSP in unified standard. The propagation characteristics of AE and the planar positioning function of AE were concerned in this work, the AE energy of material was obtained from detected waveforms and characteristic parameters of AE by calculation, which is helpful to realize the on-line monitoring of LSP.