Abstract:Abstract: Based on vegetation investigation, the composition and biodiversity of main forest communities surrounding the Eastern Liangzi Lake in Ezhou city were analyzed. The relation between forest community structure and biodiversity was also studied. Based on comparing the synthetic biodiversity of different forest communities, the factors effecting forest community biodiversity were discussed preliminary. Principal component analysis method was applied to calculate and rank the synthetic biodiversity, which was a positive try measuring synthetic biodiversity for forest community.