Iron oxide layers fonned on mild steel substrates in alkaline media by chemical method were studied. The effects of some factors such as: NaOH, NaNO3, NaNO2 solution concentration, temperature on synthesized magnetite films on mild steel were investigated. Morphology and structure of the oxide film on mild steel, were fonned in solution of (500 g/L NaOH, 100 g/L NaNO3, 200 g/L NaNO2), at temperature 120°C, in 40 minutes were studied. The results showed that synthesized magnetite films have thickness 1.29 +/- 0.20 um, crystal unifonn globes, average diameter 20 nm.