Abstract: Alternanthera philoxeroides is an invasive plant species in China.To confirm whether it can survive the flooding condition on riverbanks,we measured the morphological adaptation,biomass reduction and survival of A.philoxeroides subjected to 30 d,60 d,90 d and 120 d submergence as well as recovery growth after de-submergence.Submergence greatly enhanced shoot elongation and new leaves generation,but it also resulted in notable decrease in total biomass and belowground biomass.Submergence had less effect on survival of A.philoxeroides,the survival of the plants was still 90% after 120 d submergence.A.philoxeroides could regrow quickly after de-submergence,but the recovery ability decreased with the durations of submergence.The results indicated that A.philoxeroides is a submergence-tolerant species,it can distribute naturally on riverbanks,but it maybe perform badly on the low-elevation site on riverbanks which subjected to prolonged submergence.