Abstract: Based on May to August monthly rainfall data in Guizhou province from 1961 to 2019,the re-analysis data from NCEP/NCAR,and long-cycle drought-flood abrupt alternations index,this study analyzes the spatial temporal variation characteristics of the abrupt drought-flood alternations in Guizhou province and its relationship with atmospheric circulation anomalies. The results show that the alternations in Guizhou have the characteristics of both phase continuity and intermittent coexist,with obvious interdecadal variation,but the times of flood-to-drought transition is less than that of drought-to-flood transition. The abrupt drought-to-flood alternations is more likely to appear in the southern and eastern parts of the province but weaker. The characteristics of the anomalous atmospheric circulation shows the drought period of drought-to-flood transition,the middle and high latitudes are zonal circulation,the area of the subtropical high is small,and the west ridge point is eastward. Guizhou province is located to the north of it,controlled by the sinking flow in lower layer. the conditions for water vapor transportation are poor,Flood period is radical circulation and the subtropical ridge is northward and smaller. Guizhou province located in the western edge of the subtropical ridge and the lower layer is in an upward movement. In the flood period of flood-to-drought situation,longitude of circulation is high and cold air is activity. The subtropical high is southward and eastward,wit the cold and warm air converging in the Yangtze River basin,which is conducive to more precipitation in Guizhou province. During the drought period,the subtropical high is northward and eastward,Guizhou province is controlled by the ridge of high pressure.