Abstract:The composition, distribution and seasonal variation of the benthic marine algae in the northern Bohai Sea coast were studied. 119 species of benthic marine algae were found in the northern Bohai Sea coast. They belong respectively to Cyanophyta, Thodophyta, Phaeophyta and Chlorophyta. The study showed that the marine algae flora of the northern Bohai Sea coast belongs to warm temperate in nature with considerable subtropical composition. There were 57 species of economic algae in the northern Bohai Sea coast and 7 newly recorded species.