We studied photoluminescence (PL) and electroluminescence (EL) properties of hydrogenated nanocystalline silicon (nc-Si:H) thin films prepared by applying the plasma enhanced chemical vapor deposition (PECVD) techniques. . A prototype of ITO/nc-Si:H/P-type Si wafer/Al EL devices was illustrated with its fundamental electrical and optical features. The nc-Si:H films exhibited PL spectra in a wavelength range of 350 ~ 700 nm with the maximum intensity at ~ 530 nm, which is attributed to quantum confinement effects (QCE) owing to the presence of nanocrystalline Si. The EL device produced EL spectra with their maximum intensity at ~ 525 nm which are similar to the PL spectra. The light emission is attributed to radiative recombination related to nanocrystalline Si contained in the hydrogenated amorphous Si (a-Si:H).