The compositional dependence of luminescent and crystallographic characteristics of the Zn x Sr 1 - x S:Ce thin films was investigated by compositional analysis, crystalline characteristics, valence state of Ce ions and photoluminescence (PL) properties. It has been found that the enhanced PL intensity by the incorporation of a small amount of Zn mainly attributes to the improvement of the crystallinity of the film and partially to the valence state of Ce ions in the host crystal.