In order to realize the online detection of laser shock processing and aim at the phenomenon of laser-induced plasma acoustic wave, the SIA-AEDAC-01 acoustic emission acquisition card is used to collect acoustic wave signals. The real-time acquisition and analysis software system for laser-induced plasma acoustic wave signal is studied and designed. The test experiment for feasibility and accuracy of the system is designed. Firstly, the laser-induced plasma acoustic wave signal propagating in air is collected by the online detection laser shock processing system, and then the system gets the laser-induced plasma acoustic wave signal energy. The residual stress of the test pieces after the treatment of laser shock processing was measured by an X-ray stress analyzer to verify the reliability. The experimental results show that the laser-induced plasma acoustic wave signal can be collected and analyzed in real-time by the real-time acquisition and analysis software system, which is designed and developed in this work, and the software system can accurately get the acoustic signal energy. At the same time, both the acoustic wave signal energy and the surface residual stress of the test pieces are increased with the laser energy, and their change curve is consistent. In conclusion, the real-time acquisition and analysis software system for laser-induced plasma acoustic wave signal can satisfy the requirements of online detection of laser shock processing with accurate and reliable performance, and meet the online monitoring requirements of laser shock processing.