(100)(C)-oriented Na0.5Bi0.5-xSmxTiO3 (NBST) lead-free ferroelectric thin films were prepared on Pt/Ti/SiO2/Si substrates by chemical solution deposition method, and their microstructural, dielectric, ferroelectric, and photoluminescent properties were studied. X-ray diffraction and scanning electron microscopy analysis indicated that both the grain size and (100)(C) orientation degree of NBST thin films were decreased by doping Sm3+ ions. Raman spectra showed that structural symmetry of NBST thin films decreased at low Sm3+ doping concentration and then increased at high doping concentration of Sm3+ ions. An appropriate amount of Sm3+ dopants was confirmed to enhance dielectric and ferroelectric properties of the NBST thin films. Among all the compositions, the Na0.5Bi0.492Sm0.008TiO3 thin film exhibited the largest remnant polarization (2P(r)) of 27.3 C/cm(2) and high dielectric constant of 1068, as well as a low dielectric loss of 0.04. Temperature- and frequency-dependent dielectric characteristics illustrated the relaxor ferroelectric behavior of Na0.5Bi0.492Sm0.008TiO3 thin film. Meanwhile, the Na0.5Bi0.492Sm0.008TiO3 thin film also showed optimal orange-red emission at 600 nm, which is originating from the (4)G(5/2) H-4(7/2) transition of Sm3+ ions.