The global atmospheric variables of observations can be decomposed physically into four components, namely zonal mean symmetric climate, asymmetric climate, zonal mean instantaneous symmetric anomaly and instantaneous asymmetric anomaly. Based on the latest ECMWF global atmospheric reanalysis ERA Interim data with 0.75°×0.75° resolution, the physical decomposition method of atmospheric winds and its application in the regional rainstorms are introduced. The result showed that the physical decomposition of ERA Interim data can better reflect the location of regional rainstorms and the relations between wind and rain. For example, the rainfall band is located along the convergence line of anomalous airflow in the lower troposphere and the anomalous airflows on both sides of a stable rainstorm band present a confrontational convergent pattern.