The work aims to improve the corrosion resistance of ZnAl-LDHs on the surface of aluminum alloys. Firstly, the 6061 aluminum alloy was placed in the hydrothermal reactor and hydrothermal treatment was conducted with deionized water for 30 minutes at 120 ℃. Secondly, the aluminum alloy after hydrothermal treatment was respectively immersed in 50 ℃ and 80 ℃ 0.005 mol/L Zn(NO3)2 solution for 4 hours to prepare ZnAl-LDHs coatings. The surface morphology, structure and corrosion resistance of the ZnAl-LDHs coatings prepared in different conditions were analyzed by XRD, SEM, EDS, EIS and polarization curve method, respectively. After hydrothermal treatment, the mixed layer of Al(OH)3 and AlO(OH) was formed on the aluminum alloy and the ZnAl-LDHs coating on such layer had better lamellar structure, higher crystallinity and finer and denser nanosheets. The results of EIS and polarization curve showed that the ZnAl-LDHs coating prepared on the surface of 6061aluminum alloy could reduce the corrosion current density and enhance the corrosion potential. After hydrothermal treatment, ZnAl-LDHs coating was formed on aluminum alloy surface in 80 ℃ solution and the self-corrosion current density was only 0.018 μA/cm2, five times lower than that of ZnAl-LDHs (0.101 μA/cm2) prepared on the surface without hydrothermal treatment. The same condition was also observed on the ZnAl-LDHs coating formed in 50 ℃ solution. A mixed layer of Al(OH)3 and AlO(OH) can be formed on 6061 aluminum surface after hydrothermal treatment and can be used as a precursor for in situ growth of ZnAl-LDHs to promote the crystallization and nucleation of LDHs, reduce the size of coating nanosheets and improve corrosion resistance of ZnAl-LDHs coatings on aluminum alloy.