Abstract: Abstract In the traditional acoustic emission source localization method, the reliance on fixed wave velocity leads to limited localization accuracy. In this study, an acoustic emission source localization method based on particle swarm optimization (PSO) algorithm was proposed, compared with the calculation results of AEwin localization software, which effectively broken through the limitation of fixed wave velocity and improved the average accuracy of acoustic emission source localization by 7.4%, and the variability of propagation speed of acoustic waves in liquids was revealed, which provided new theoretical support and practical guidance for the development of acoustic emission source localization technology.