Laser remelting (LR) pretreatment, micro-arc oxidation (MAO) treatment and layer double hydroxides (LDH) sealing post-treatment are conducted on AZ31 alloy surface in sequence. The results show that the corrosion resistance of prepared LR/MAO/LDH composite layer is significantly improved. Compared with the solution-aged AZ31 alloy and LR/MAO layer, the corrosion current densities of AZ31-LR/MAO/LDH were reduced by 4 and 2 orders of magnitude, respectively, and the self-corrosion potentials were increased by 1.23 V and 0.25 V, respectively. Laser remelting pre-treatment increased the average thickness of the MAO layer by 5–10 μm. LR/MAO/LDH composite layers can effectively improve the corrosion resistance of AZ31 alloy, and have the potential for application.