The invention discloses a pollution source online monitoring system. The system comprises an online monitoring module, an information management module and a knowledge base management module, the online monitoring module facilitates real-time online monitoring of pollution sources such as waste water and exhaust gas and the like, through collection, transmission, statistics, analysis and the likeof pollution monitoring data, unified management, data over-standard early warning, monitoring equipment management and counter-control of pollution source monitoring data are achieved, through the information management module, multi-source heterogeneous data such as existing emission declaration, pollutant survey and the like is conveniently effectively integrated to form a global unified pollution source file, global sharing is achieved, dynamical maintaining is conducted on pollution source file information, the accuracy and integrity of the pollution source information are ensured, and quick query, scheduling and adjustment are conveniently conducted on emergency management and danger prevention management of pollution sources through the knowledge base management module to prevent greater loss of the pollution sources.