Abstract: Mangroves on Qi’ao Island had suffered heavy losses due to the chilling injury in 2008, and almost all the Sonneratia caseolaris trees were frozen to death. After 18 months of the chilling injury, nature vegetation of Sonneratia caseolaris plantation in the chilling injury areas are chiefly Acanthus ilicifolius and Spartina alterniflora, with a few other plants associated, 10 species which belong to 9 genera and 7 families were found in the mud flats. Vegetation on the chilling injury areas can be divided into five types according to its characteristics, they are Acanthus ilicifolius+Spartina alterniflora community, the consociation Spartina alterniflora community, the consociation Acanthus ilicifolius community, Acanthus ilicifolius sparse community and bare flat. Plants in the first three communities all have the characteristics of high vegetation coverage and high density, which is harmful for the dispersal of mangrove seedlings such as Kandelia candel and Aegiceras corniculatum. Spartina alterniflora has the trend of expansion to Acanthus ilicifolius communities and bare mudflats by vegetative propagation after they first settled on the mudflats. Acanthus ilicifolius and Spartina alterniflora multiplied rapidly in the chilling injury areas of Sonneratia caseolaris plantation, and they could occupy the mudflats for a long term.