The changes of mangrove cover, plant species composition of mangroves and sedimentation rate in Xuan Thuy National Park were investigated and analyzed to evaluate the responses of mangrove ecosystems to climate change and sea level rise in Xuan Thuy National Park. The results confirmed that mangrove area in Xuan Thuy National Park increased about 600 ha in the period 1995 - 2010. It was recorded with a total of 12 true mangrove species belonging to11 genera and 9 families in Xuan Thuy National Park. In comparison to the previous observations, two species Lumnizera littorea and Nypa fruiticans are no longer found in this study. The results also indicated that mangroves could migrate seaward because the sedimentation rate in Xuan Thuy National Park is much higher than that of sea level rise (i.e., the sea level has dropped compared to the mangrove surface).