Water samples were collected in summer and winter in Zoige Alpine Wetland. Both the traditional cultivable and microscopic method and modern molecular approach were used to reveal the algal diversity in the wetland. For the samples collected in summer, single-cell Chlorophyta was cultured, isolated and identified. The results showed that there were at least four kinds of Chlorophyta, which were Chlorella vulgaris Beij., Planktosphaeria gelatinosa G. M. Smith, Scenedesmus abundans Kirchne and Scenedesmus bijuga Turp. They all belonged to Chlorococcales. The dominant species was Chlorella vulgaris Beij., which had been purified. For the samples collected in winter, the microscopic results showed that the dominant populations were diatoms, which is in accordance with the principle that the dominant populations of algae are diatoms in low-temperature seasons. Cyanobacterial 16S rRNA gene clone library showed that the dominant group was Bacillaripiophyta (35.3%). And Cyanobacteria contained the orders of Chroococcales (5.9%), Nostocales (11.8%), Osillatoriales (11.8%) and Unclassified Cyanobacteria (35.3%). There were some clones related to those from frigid habitats, such as Leptolyngbya-related clones.