Algae and mosses are not only two common pioneer plants in the process of vegetation succession but also two groups with the highest biomass in the biological soil crust. As pioneer plants, algae and mosses are indispensable in the process of establishing the biological soil crust, which plays an important role in the desert ecosystem, namely, indicating vegetation type, soil holding, preventing from erosion by water or wind, and sand fixation. This paper reviews the recent research into algae and mosses which in arid and semi-arid areas and focuses on the ecological separate functions and relations of alg-ae and mosses. Some suggestions are proposed for researching algae and mosses, especially research into the symbiotic mechanism of algae and mosses in the biological soil crust. Ecologically, such research has important significance and prac-tice value for further analyzing the influence and demonstrating the ecological relations between algae and mosses.