Abstract: The forecasting system of pollutant origins was established based on numerical model of regional air quality and tagging technology of emission sources. It realized the realtime forecasting of pollutant origins over Beijing-Tianjin-Hebei area. To cope with the urgent time restriction in forecasting, a series of special designs were made in emission preprocessing, source apportionment prediction and automatic routine operation. These included developing the fast emission preprocessing technology, determining the solution of source apportionment according to regions and sectors by trial calculation, compiling and running the regional air quality model via a hybrid usage of two mainstream solutions of parallel computation, and designing a distributed solution to handle multiple tasks in routine forecasting running for sufficient use of computation resources. All of the optimization measures effectively reduced the time of forecast runs. At present, the forecasting system is in routine operation stage. It predicts the air quality for the 3 days ahead and the origins of major pollutants according to regions and sectors each day before 0800LCT. The system had been applied in some big events, such as for the air quality guarantee and post-assessment for the period of victory parade of war against Japan , the pre-warning of severe air pollution from the end of November to the early of December, 2015.