The marine algal flora and community structure were investigated at three sites in Ulsan on the southeast coast of Korea between August 2005 and July 2006. Ninety-one benthic algae species were identified, including 14 Chlorophyta, 21 Phaeophyta, and 56 Rhodophyta species. Of the 91 seaweeds, 19 species were found throughout the survey period. The wet weight biomass ranged from 310.8 to 2,960.4 g $m^{-2}$ during the study period. The maximum biomass was recorded at Sinri, and the minimum was recorded at Daesong. The R/P, C/P and (R+C)/P values reflecting flora characteristics were 2.67, 0.67, and 3.33, respectively. The flora investigated could be classified into six functional groups: coarsely branched (46.2%), thick leathery (22.0%), filamentous (16.5%), Sheet (7.7%), jointed calcareous (4.4%), and crustose (3.3%) forms. A cluster analysis produced two groups that differed meaningfully: one included the site Sinri-summer and the other included the sites Daesong and Jinha.