Abstract: The six most widespread species were chosen around the world of genus Scytonema of family Scytonemataceae, order Hormogonales, phylum Cyanophytain, to explore the relation between Scytonema and environmental factors. Based on the data of geographical distribution of six species in the world and environmental factors, the correlation analysis, principal component analysis and linear discriminant analysis were used to analyze the influence of these environmental factors on the geographical distribution of six species of genus Scytonema and the corresponding geographical distribution and growth environment. The correlation analysis, principal component analysis and linear discriminant analysis revealed the noticeable correlation between the geographical distribution and growth environment of genus Scytonema. The results demonstrated that annual mean temperature, temperature seasonality, temperature annual range, maximum temperature, minimum temperature, isothermality, water vapor pressure, solar radiation and wind speed were the important environmental factors affecting the geographical distributions of these six species.