Aluminum granules were coated with a plasma polymer of tetraethoxysilane (TEOS) for the corrosion protection in alkaline solutions. For the examination of the corrosion resistance, the coated aluminum samples were dipped into alkaline solutions and the dissolved amounts of aluminum and L-value (lightness) of the aluminum surface were measured. At pH 10, almost no aluminum was found in the solution, and the L-value was little affected and the metallic appearance of aluminum was retained. At pH 11, some aluminum ion was found in the solution but its amount was reduced significantly compared with the uncoated one. From the X-ray photoelectron spectroscopic study, the plasma-polymerized TEOS film was found to still contain a large portion of organic groups.