A Cu2ZnSnS4 (CZTS) film was fabricated by sulfurization of two stacked layers of Cu (Zn, Sn) (CZT) alloy precursors. The sulfurization was performed in an evacuated and sealed quartz ampoule with sulfur powder, in which samples were annealed at 450 degrees C, 500 degrees C, or 550 degrees C for 1h and then allowed to cool naturally. The XRD patterns of all samples are well matched to those of the CZTS crystal. In this study, it is confirmed that the Sn in the metal precursors is lost in the form of SnS gas and a SnS2 solid that crystallizes upon the combination of SnS and S when the CZTS film is annealed. The band gap energy of CZTS absorber was determined to be 1.370-1.414eV. The surface morphology and grain shapes of these CZTS thin films were analyzed using SEM images and XRD patterns.