Multi-Walled Carbon Nonotubes (MWCNTs)/AZ31 composites were fabricated by joining preform of MWCNTs during melting. The corrosion behaviors of the composites with equal channel angular pressing (ECAP) for different passes were studied by immersion and electrochemical corrosion experiments in 3.5%NaCl (mass fraction) corrosion medium. The effects of ECAP on corrosion resistance of MWCNTs/AZ31 composite were investigated. The surface morphologies of the composites before and after the corrosion testing were observed and analyzed by digital camera and scanning electron microscope (SEM). The results show that ECAP effectively improves the corrosion resistance of MWCNTs/AZ31 composites. After 4 passes-ECAP, the average corrosion rate of MWCNTs/AZ31 composites immersed in 3.5%NaCl corrosion medium for 24 h changes from 0.6035 mg/(m2·s) to 0.2963 mg/(m2·s) and the corrosion current density (Icorr) is decreases from 3.363 μA/cm2 to 2.269 μA/cm2