Polyaniline (PAni) film was successfully electrodeposited on the surface of steel substrates in oxalic acid electrolyte by cyclic voltammetry at different potential sweep rates (dE/dt) (10, 20 and 30 mVs-1) and different pH values (1.55, 2.55 and 3.55). The coated steel with PAni was characterized by Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. The corrosion resistance of the electrodeposited layers was evaluated by potentiodynamic polarization in 0.1 M NaCl aqueous solution. The results showed that with increasing pH and sweep rate the amount of corrosion rate decreased and increased respectively. Moreover, the correlation between variation of anodic charge (Qa) with pH and sweep rate has been evaluated. The variation of anodic charge confirmed that the growing rate of polymer decreased with increasing sweep rate and pH. The result of potentiodynamic polarization showed that the coated steel with synthesized PAni in pH 3.5 and sweep rate 0.01Vs-1 had better protective properties against corrosion.