Surface observation and air quality data are applied for the analysis of advective transport characteristics in Beijing during the 2013-2014 winter months with cluster analysis. Meanwhile, potential source contribution function (PSCF) is used for the analysis of potential source area. The results show that air masses which influence Beijing mainly come from southwest, east and northwest, and the probability for heavy pollution weather in southwest and east paths are 56.58% and 43.80% respectively, which indicates the two directions are typical pollutants transmission paths. It is also revealed that high PSCF values caused by underlying emission and small air mass velocity cover the western Shandong, central and southern Hebei, Tianjin and other places. These places are affected by air masses from southwest and east. Combined with emission intensity of PM2.5, transmission weather index is designed based on the former conclusions. It is found that the index is consistent with PM2.5 concentration, and has a forecast of about 6 hours in advance. Therefore, combining transmission weather index with weather analysis may lead to a better understanding of heavy air pollution and play a reference role in forecasting operation and assessment.