In order to further improve the operation reliability of substation site equipment, abnormal sound online monitoring and positioning system for substation equipment was designed. This system consists of on-site monitoring unit, system server and client three parts. Three key technologies were researched and developed: substation abnormal sound automatic identification technology, substation abnormal sound video positioning technology and substation abnormal sound message warning system technology. Abnormal sound online monitoring and positioning system for substation equipment has reasonable structure and good results.