Based on the daily 6 h 850 hPa geopotential height field data from ERA-Interim reanalysis data during 1979—2013,the two-dimensional cyclones affecting the Yangtze-Huaihe River valley (YHV) in spring are extracted by using the automatic identification method of outermost closed contour of cyclones.The relationship between interannual anomaly of subsynoptic-scale cyclone activity and precipitation anomaly in YHV is studied.Results show that the subsynoptic-scale cyclone activity has an obvious effect on spring precipitation in most areas of YHV,with a contribution rate of more than 25%.The subsynoptic-scale cyclone activity has corresponding significant regional cyclonic vortex and convergence motion in the lower troposphere,which provides favorable dynamic conditions for the local precipitation enhancement.The interannual variation of subsynoptic-scale cyclone intensity has a significant positive correlation with the precipitation anomaly and the occurrence frequency of heavy precipitation in the southeast of YHV in spring.When the subsynoptic-scale cyclone intensifies in YHR,an anomalous inverted trough circulation appears from the Qinghai-Tibet Plateau to the lower-middle reaches of the Yangtze River in China,which is conducive to the formation of cyclonic circulation anomaly in YHV.Simultaneously,the atmospheric baroclinicity increases in the lower troposphere when the southwest warm and moist air flow in southern China strengthens,which promotes the enhancement of subsynoptic-scale cyclone in YHV.The anomalous heating of air column over the Qinghai-Tibet Plateau in spring,which leads to the decrease of potential height in the lower troposphere and the strengthening of southwest flow in southern China,may be the main reason for the enhancement of subsynoptic-scale cyclone activity in YHV.