[Objective] This study aimed to reveal cyanobacterial biomass and community structure within shielding nylon mesh in different shrub roots with different plantation ages and within shielding nylon mesh, and to clarify the colonized states of cyanobacteria in different shrub roots and within nylon mesh.[Methods] Biomass of cyanobacteria were measured by counting and volume conversion with microscope and these cyanobacteria were identified according to their morphology, structure, size and other characteristics with toxomony book "freshwater algae of China" and so on.[Results] Number of cyanobacteria was as the highest as 9.84×10⁸ cell/g in the root of Hedysarum scoparium which was planted in 1956, and were the lowest(3.16×10⁸ cells/g) in the root of Hedysarum scoparium planted in 1981 and in the root of Artemisia ordosic planted in 1987. Average total volume of cyanobacteria was the highest(1.04×10¹³ μm³/g) in the root of Artemisia ordosic planted in 1964, and the lowest(6.00×10¹¹ μm³/g) in the root of Carnage intermedia planted in 1964. The percentage of filamentous cyanobacteria was the highest(98.4%) in the root of Artemisia ordosic planted in 1987, and the lowest(38.75%) within nylon mesh. Totally 25 cyanobacteria, mainly belonging to Chroococcales, Oscillatoriales and Nostocales, were found. Among them, Oscillatoria princeps is the most dominant cyanobacteria, and Nostoc punctiforme, Microchatetenera thuret and Calothrix linearis were recognized.[Conclusion] Cyanobacterial biomass and their diversity of three kinds of shrub roots were found higher, probably their rhizosphere habitats are favorable for cyanobacterial colonization and reproduction.