A titanium-salt conversion coating , which was prepared on Al 2024 with a conversion solution made mainly of TiOSO4 , NaF under the condition of 60℃ , pH5~5.5 , UV irradiation and 5 minutes , could undergo more than 96 h of neutral salt spray test. The energy disperse spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) analysis showed that the primary elements of conversion coating were O, Ti, Al, F, Mg, Cu and Ti element mainly existed in the form of TiO2. The result of electrochemical tests demonstrated that the more positive corrosionpotential and ananode passivation area formation of 2024 Al alloy treated by conversion reaction under UV irradiation made the corrosion resistance of 2024 Al alloy improved significantly.