The present study investigated the floristic composition of the Sunderban mangrove forest after cyclone Sidr in order to infer about the severity of the damage of the forest plants. Data was collected by vegetation analysis using quadrat (10 m X 10 m) and focus group discussion with the local people. Data showed that the study area is rich in plant diversity with 5 to 8 species and dense in population having 712 to 1484 individuals per quadrat. Data also revealed that at least one tree was broken or uprooted in an area of 100 square meter (10 m x 10 m) indicating the severity of the damage by Sidr in the context of whole forest area. It is also found that tall plants like Keora (Sonneratia apetala) were most affected species. This study suggests that vegetation analysis should be conducted with more sampling sites after any devastating cyclones in order to monitor the damage of the tree and its consequences on the floristic composition.