Corrosion inhibition of mild steel in normal hydrochloric acid solution at 303 K by Brachychiton essential oil (B.O.) has been studied by potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) measurements. The oil essential of Brachychiton (B.O.), was analyzed by chromatography (HPLC/UV) and FTIR spectra. The results show that this oil is characterized by palmitoleic acid, palmitic acid, stearic acid, oleic acid being the major constituents. The inhibition efficiency increases with the increase of inhibitor concentration. Potentiodynamic polarization studies clearly reveal that the presence of this inhibitor acts like a mixed inhibitor. The effect of temperature on the corrosion behavior of mild steel in 1M HCl with and without oil in the temperature range 303-333 K, indicates that inhibition efficiency increases with temperature. While SEM analysis the formation of protective layer over the steel surface. The adsorption of natural product son the mild steel surface obeys to Langmuir’s adsorption isotherm.