Abstract: Dashanbao Grus nigricollins National Nature Reserve is located in Zhaotong city of Yunnan,belonging to sub-alpine meadow-bog with diversified habitats and complex natural environment.Algae resource in this area is very rich,and especially characterized by the wide distribution of desmids.After studying the desmids in the water masses of Dahaizi and Tiaodunhe,thirty three species of desmids were identified which belonged to nine genera of Desmidiaceae and Desmidiales,and other two species belonged to two genera of Mesotaeniaceae and Zygnematales.The ecological environmental effect on the distribution of desmids in Dashanbao was analyzed.The water quality of Dahaizi and Tiaodunhe of Dashanbao were analyzed and evaluated according to the proportion of blue algae and chlorella.