Abstract: Epiphytic algae on three stream macroalgae (Chara vulgaris, Cladophora fracta and Batrachospermum arcuatum) were collected from two sites in Xin'an Spring, North China, during July 2004 to April 2005 (one sampling per season). The species composition, distribution and effect of environmental factors on the epiphytic algae were studied. Several environmental factors were monitored at the same time. The species number of epiphytic algae on the three stream macroalgae was different because the habitat structure had pervasive effects on community composition and diversity. The epiphytic algae on Chara vulgaris resulted in 49 species, 37 species on Cladophora fracta and only 6 species on Batrachospermum arcuatum, respectively. The predominant species of epiphytic algae on the three stream macroalgae belongs to Bacillariophyta. In terms of the seasonality, there was an obvious seasonal trend in species number of epiphytic algae: spring > autumn > summer > winter. The results also indicate that there were some environmental factors influenced the epiphytic algae in different extents. The key factors were current velocity, maximum depth, and specific conductance.