The diversity of the epiphytic bacteria was studied based on the morphological characteristics and 16S rDNA sequence analysis, which were isolated from Ulva spp. (Enteromorpha spp.) distributed in Zhujiajian Zhoushan, Guohua power plant of Ninghai and Nansha Fenghua in China. The 65 isolated strains were grouped into 26 morphotypes, which had high similarities with strains of 23 generas such as Acinetobacter sp., Alteromonas sp., Vibrio sp., Pseudoalteromonas sp., Exiguobacterium sp., Bacillus sp., Erythrobacter sp., Micrococcus sp., Pseudomonas sp., Idiomarina sp., Phaeobacter sp., Roseivirga sp., Silicibacter sp. and so on. The results suggested that:(1) The diversity of Ulva spp. (Enteromorpha spp.) epiphytic bacteria was most abundant in Guohua power plant of Ninghai, and the Shannon-Wiener index was shown at 93.98%. (2) The Flora of Ulva spp. (Enteromorpha spp.) epiphytic bacteria was relevant with its growth and living environment. Although the community structure and dominated bacterica from different origins were various, the main species of bacteria belonged to the phylum of Proteobacteria. There were still some unidentified strains in this study, which need further investigation.