We report on the growth mechanism of NiAl-based layered nanostructures on rigid substrates using a low-temperature hydrothermal method. NiAl-layered double hydroxide (LDH) structures were grown with various source concentrations and growth times. Structural and optical investigations showed that uniform NiAl-LDHs were grown on the substrates because Al(OH)(3) was sufficiently supplied from the aluminum thin film seed layer when the Ni source concentration was low and in the initial stage of the growth. However, a bilayer of NiAl-LDH and alpha-Ni(OH)(2) was formed when the Ni sources were sufficiently supplied and the growth time was long enough because of the deficient Al(OH)(3) sources at the growth front.