Abstract: Xin'an Spring located in the cross of Lucheng, Licheng and Pinshun county in Shanxi Province, North China.The spring is a large cool spring with rich algal resources.We selected 7 sites and sampled the algae four times from 1995 to 2003.In the research, 36 species of macroalgae have been identified, comprising 6 divisions, 11 families and 18 genera.Chlorophyta was the most diversified division, with 19 species in 4 families and 8 genera.Cyanophyta was ranked as second, with 11 species in 2 families and 5 genera.The third was Xanthophyta, with 3 species in 2 families and 2 genera.Which was ranked as the last were Rhodophyta, Bacillariophyta and Charophyta, they respectively only have 1 species in 1 family and 1 genus.The macroalgal flora of Xin'an Spring was mainly divided into 4 kinds of communities: Cladophora community, Vaucheria community, Spirogyra-Zygnema community and Chara community.The results show that the species diversity have become reduced.

Key words: Stream macroalgae, flora, community, Xin'an Spring