Abstract:Cyanobacteria is one of the oldest organisms on earth. It is prokaryotes of oxygen-producing photosynthesis with relatively simple morphology and structure. Until now, there are relatively few studies on the diversity of cyanobacteria in fresh-water lakes. In this study, five filamentous cyanobacteria species were isolated and purified from Jinyang Lake, Shanxi Province. The microstructure (such as cell shape, size and sheath postural) were directly observed under the microscope, which was roughly divided into three families (Leptolyngbyaceae, Pseudoanabaenaceae and Desertlaceae). Further, the phylogenetic tree was constructed with 16S rRNA gene as marker for molecular identification. The results showed that the morphological identification of the isolated algae strains was consistent with the results of 16S rRNA sequence phylogenetic analysis. Among them, 2 strains were leptolyngbyaceae (JYH005 and JYH012), 2 strains were pseudoanabaenaceae (JYH008 and JYH022), and 1 strain of filamentous cyanobacteria was desirtiferaceae (JYH010).