Cu2SnS3 (CTS) thin films are prepared by sulfurizing CTS precursor films which are obtained using a sol-gel technique in air atmosphere. The effect of the sulfurization time on the properties of CTS thin films and solar cells is investigated. The uniform and dense CZT thin film is obtained by sulfuring at 575°Cfor 20 min. The corresponding solar cell shows the highest power conversion efficiency (3.68%), with a short-circuit current density (Jsc) of 30.25 mA/cm2, an open circuit voltage (Voc) of 254 mV, a fill factor (FF) of 47.9%, and a peak external quantum efficiency (EQE) of 70%.