Abstract Fe4[Fe(CN)6]3 nanoparticles were prepared with potassium ferrocyanide as the single precursor. The effects of precursor concentration and temperature on the particles were investigated. The reaction mechanism was explained. Calculation showed that formation of Fe4[Fe(CN)6]3 precipitates and volatile HCN greatly reduce the electron potential of Fe3+/Fe2+ and increase the reaction extent of the oxidation of ferrous ions.