It is a new development direction to apply acoustic emission nondestructive testing to mechanical seal monitoring.The research of acoustic emission in the sealing field was reviewed from the aspects of experimental and theoretical research.The research results of each stage were summarized from the early experimental exploration to the later signal denoising,signal analysis and signal recognition,and the experimental research on the phase transition of mechanical seal was introduced.The future development direction of mechanical seal monitoring technology based on acoustic emission is suggested,such as the application of big data technology to acoustic emission signal processing and analysis,and the application of acoustic emission technology in different directions of mechanical seals,such as liquid film phase transition monitoring