Three pretreatments including manual brushing deoxidizing, sanding deoxidizing and dipping deoxidizing were respectively applied on Al-Li alloy 2198 . Subsequently, Alodine1200 s chromate conversion solution was manually brushed on the samples. The corrosion resistances of the chromate conversion coated samples in 3 . 5 % NaCl solution were studied by polarization curve and electrochemical impedance spectroscopy ( EIS) , and the influence of the pretreatment on corrosion resistances of the samples was analyzed by scanning electron microscopy ( SEM) . The results show that Eb of the sanding deoxidizing sample is the most positive and J_corrof this sample is the lowest . The radius of capacitive arc in Nyquist plot and the modulus of corrosion resistance in Bode plot arrive at the maximum because of the sanding deoxidizing pretreatment . Under the same condition, the phase angle of corrosion resistance in the low frequency range is most close to-90 ^o . Therefore, the corrosion resistance of the sanding deoxidizing sample is the best .