Five soil samples (S1-S5) collected from different locations in Egypt to investigate the effect of their physio-chemical parameters on the diversity of algae and their divisions. The results obtained showed that the physio-chemical parameters of the soil have its influence on the diversity of algae. The most varied parameters between the studied locations were soil pH and the nitrogen contents. The collected algae were 36 species representing 25 genera classified over four divisions. The dominant division was Cyanophyta, which represented by 18 species from 11 genera, followed by Chlorophyta, eleven species belonging to seven genera, then Bacillariophyta and Xanthophyta. The variation in the soil characters between the studied locations affects both the algae richness and diversity. Correlation analyses have been done to investigate the most effective parameters affecting the algae richness and diversity. This study showed that, the soil texture, moisture content, organic matter and nitrogen concentration are the most effective factors in controlling the diversity of soil algae at the studied locations.