Abstract: In order to explore drainage management in those regions vulnerable to flooding and subsurface waterlogging, experiments of rape suffering from continuous subsurface waterlogging were implemented by test-pits and small field plots. Results show that the most sensitive growing period of rape suffering from continuous subsurface waterlogging to influence crop yield is blossoming stage and blossoming-fruiting stage; normal blossoming and fruiting of rape were affected due to continuous subsurface waterlogging at blossoming-fruiting stage, it led to reduction of effective fruits and made rape yield decrease; there was a little influences upon rape yield when rape suffers from subsurface waterlogging in short time (within 7 d) in spring, reduction of yield less than 10%, but a marked influence upon rape yield was made when 2～3 subsurface waterlogging processes occurred continuously in the season, yield reduction arrived at 15.4%～36.8%. Therefore, it is of important significance for rape production that drainage management in rape field is made well in spring.