The community structure of benthic marine algae was investigated at Taean Thermal Power Plant and other places around Taean Peninsula, the west coast of Korea. Total of 100 species including 3 Cyanophyta, 14 Chlorophyta, 18 Phaeophyta, and 65 Rhodophyta were identified. The number of species was highest with 78 species at the Power Plant intake, followed by 61 at the discharge, 56 at Bunjeondo, and 50 at Maoe. It was noteworthy that a subtropical species Caulerpa okamurae was collected at the intake in autumn and it was the first observation in the west coast of Korea. The pattern of vertical algal distribution showed Gloiopeltis furcata occurred in the upper intertidal zone, Sargassum thunbergii and Corallina spp. in the middle and lower zone and Enteromorpha spp. in the lower middle zone. These were all dominant species except for Enteromopha spp., which was subdominant species. Other subdominant species were Chondrus ocellatus and Neorhodomela aculeata. The average diversity indices were between 0.70 and 1.20 at each area based on their dry weight. The similarity index was 0.79 between the algal flora of this study and that of 1987, indicating that the condition of the benthic environment remained unchanged since then. This area maintained its environmental quality, so the algal community remained same with similar structure. This study area seemed a suitable place for long term monitoring of the benthic environment where industrial facilities such as a power plant might affect the benthic algal community.