In this study, nanoporous anodic aluminium oxide (NAAO) layers were synthesized by mild and mild-hard anodization two methods in a solution of oxalic acid and NAAO-Sm3+ nanocomposite were synthesized by boiling the (NAAO) layers in a solution of samarium nitrate. Then, the samples were annealed at different temperatures under argon atmosphere. For characterization of the morphology, phase structure, energy levels, and emission wavelengths of the NAAO-Sm3+ nanocomposite layers from a field emission scanning electron microscope (FE-SEM), x-ray diffraction (XRD), and photoluminescence (PL) spectroscopy were respectively used. The results indicate that increasing annealing temperature leads to decreasing the PL spectra intensity at wavelengths of 397 and 433 nm that related to (oxygen vacancies) but the PL intensity of the NAAO-Sm3+ nanocomposite layer is increased at 400 nm wavelength. With the excitation of the NAAO-Sm3+ nanocomposite layer at 400 nm wavelength, four main emission bands of the 4F-4F intra-configuration transitions of ions Sm3+ were clearly observed. These transitions include 4G5/2 → 6H5/2 (556 nm, green) and 4G5 2 → 6H7/2 (601nm, orange), 4G5/2 → 6H9/2 (647 nm, reddish), and 4G5/2→ 6H11/2 (709nm, red), respectively