Quantitative and qualitative characteristics of soils influenced by soil mic ro-algae were studied. Four different algae (Chroococcus, Chlor ococcum, Navicula and Chalmydomonas) and one alga mixture, which were formed by the above four algae species, were cultivated in two different medium s (soil and double distilled water), under regular illumination or dark conditio n respectively. We estimated the environmental pH, the microorganism biomass (no t including algae), and the organic matter content. We got the results by making graphs and extreme-difference analysis after 0, 20, 40 and 60-days cultivatio n. The results show that there are some similarities among the three data. The i nfluence of the algae difference on the environmental pH changing and the microo rganism biomass rising are stronger than those of the medium and illumination di fferences. The influence of the medium difference on the environmental organic m atter content is stronger than those of the algae difference and the illuminatio n difference. And the three data changing in soil are more obvious than in water .