Abstract: With various preparing methods emerged，there has been a fast development in nanoparticals preparing techniques． Biological method become a popularized object to research by scholars because of many advantages of biosynthetic nanoparticles such as a wide source of raw materials，mild reaction conditions，nonagglomerated nanoparticles，and less toxic byproducts． The synthesis methods and mechanism of iron nanoparticals by using microorganism and plant extracts at domestic and abroad are expounded，and application of iron nanoparticles in the field of environmental protection were reviewed． Finally，the indepth study on synthesis method of iron nanopaticals in the future was prospected．