Abstract: The relationship between algae and iron accumulation has attracted great attention for long time both in the geological and biological sciences. A vast amount of ferric sedimentary structures and algal fossils found in ferrolites have been attributed to the activity of cyanophytes.The experiments conducted in this study are designed to be dependent on the conditions that are believed to be algal specific actions for the formation of iron ore-In the experiments, Spirulina platensis were cultured under the simulated conditions of high PCo2 and low O2 concentrations, using low concentrations (Fe2+ 6μg/g) of ammonium ferrous sulfate in a controllable system.The results obtained show that algae can alter the microenvironment and modify the conditions for their continuations including the pH,the equilibrium system of ions, and redox potential during their logrithmic growth phase, thereby promoting ferric oxidation (Fe2+→Fe3+), and formation and deposition of a large amount of ferric complex compounds and other ferric compounds. Deposits and aggregates of iron on the bottom of containers can often be seen, obviously differing from the contrasts. Iron accumulated by algal adsorption and absorption can be up to 550μg/g. d.W.The experimental results indicate that algae may have played an important role in iron accumulation and ferrolite formation.