Mg-Al layered double hydroxide intercalated with NO₃⁻（Mg-Al LDHNO₃）coatings were formed on AA6061 alloy by electrochemical precipitation at applied voltages of 5 and 10 V to enhance its corrosion resistance. The effects of water content and total concentration of Mg（NO₃）₂ and Al（NO₃）₃（TMAIC）in the electrolyte on the coating morphology and the corrosion behavior were investigated. The water content in 2-propanol-based electrolytes was varied to 2.4%, 20%, and 100%, and the TMAIC was set to 2.4 or 24 mmol/L. In electrolytes containing 2.4% or 20% water and 24 mmol/L TMAIC, low electrical conductivity localized water reduction reactions on intermetallic particles（IMPs） and preserved the passive film on the Al matrix, leading to the preferential formation of island-like LDHNO₃ on IMPs. In contrast, in 100% water with 24 mmol/L TMAIC, higher conductivity enabled water reduction across the surface, resulting in a continuous LDHNO₃ layer. Polarization tests in 0.1 mol/L NaCl solution revealed that crack-free, island-like LDHNO₃ effectively suppressed the oxygen reduction reaction on IMPs, resulting in a corrosion current density ten times lower than that of the as-polished specimen. Continuous LDHNO₃ layers, in contrast, showed higher passive current density, indicating passive film degradation due to increased pH during electrochemical precipitation.