Abstract: The effect of rare earth chlorides on corrosion resistance of of the methacryloxy propyl trimethoxyl silane film on AA 6061 surface was studied by means of polarization curves,CuSO4 dropping and salt-water immersion test. The results showed that doping a certain content of CeCl3 in the preparation of the methacryloxy propyl trimethoxyl silane film could improve the corrosion resistance of silane film effectively. Scanning electron microscopy (SEM) indicated that the methacryloxy propyl trimethoxyl silane film had some cracks on its surface,and the modified silane film with a content of CeCl3 was dense and uniform. Under the technical conditions determined by this experiment,the optimum content of CeCl3 in the silane solution was 0.2%.