Forecasting Contamination Discharge of Insulators with Insulator Contamination Discharge Monitoring Method based on acoustic emission technology is the new development direction of transmission line maintenance at home and abroad. On the basis of analyzing the produce and propagation characteristics of Insulator contamination discharge acoustic emission signal, this paper developed a set of focusing acoustic sensor device applied to this monitoring method, and bySinstallingSandSrunning on site,Sit showsStheSfeasibility and practicalitySofSthe device.