Qualitative and quantitative algal survey was conducted from March 2010 to December 2010 on a man-made artificial beach in the Hwawon Resort Complex in order to understand seasonal changes of algal flora. The seasonal change of algal vegetation was compared with intact natural habitat near from the experimental sites. Total 15 algal species were found at the artificial beach; 8 Chlorophyta, 3 Phaeophyta and 4 Rhodophyta. And 38 algal species were found at the natural habitat; 7 Chlorophyta, 9 Phaeophyta and 22 Rhodophyta. Dominant algal species at the artificial beach were Ulva compressa, U. intestinalis, U. prolifera, U. pertusa in winter and Urospora penicilliformis, U. intestinalis, U. compress in summer. In natural habitat, dominant algal species were U. pertusa, U. compressa in winter and Sargassum thunbergii, Ishige okamurae in summer. (R+C)/P explaining spatial distribution of seaweeds was 3.7~4.0 (warm-temperature) in the artificial beach and 2.6~3.4 (polar-temperate) in the natural habitat, respectively. The flora of artificial beach could be classified into the filamentous form (64.4%), the sheet form (21.9%), and the coarsely branched form (13.7%). There was significant difference from the two habitats representing dominant species, distributions and ratio of functional-form groups.