Abstract: The species diversity of aquatic sarcomastigophoran in Scenic Spots and Historic Sites of Maiji Mountain was studied by observation in vivo, and 100 species including 2 unknown ones were identified. 59 species were identified in Mastigophora, belonging to 2 classes, 9 orders, 15 families and 31 genera. There were 52 species in Phytomastigophorea, and 36 species belong to Euglenida,accounting for 61.02% of M astigophora, so Euglenida was the dominant group. There were only 7 species in Zoomastigophorea, and the dominant group was unobvious. 41 species were identified in Sarcodina, belonging to 4 classes, 6 orders, 19 families and 32 genera. There were 31 species in Lobosea, and 16 species belong to Amoebida which was the dominant group,accounting for 39.02% of Sarcodina, Arcellinida (12 species) was the subdom-inant group, accounting for 29.27% of Sarcodina. 71, 56, 13 species were identified in the south hillside (Jialingjiang River systems), north hillside (Weihe River systems) and Watershed of Maiji Mountain, respectively. The species com-position of the community were very different in three areas. The species composition of aquatic Sarcomastigophora in Sce-nic Spots and Historic Sites of Maiji Mountain and were quite dissimilar to that in the Yangtze River, the Yalu Tsangpo River, Yellow River and other river systems. The results showed that there were rich in species, endemic species and rare species in the community of aquatic Sarcomastigophora, which indicated the prominent uniqueness of the community of aquatic Sarcomastigophora in Scenic Spots and Historic Sites of Maiji Mountain.