Cu₂SnS₃ (CTS) based thin film solar cells were successfully fabricated through a facile solution processes followed by a post-sulfurization treatment. The influence of sulfurization temperature and time on the structural, compositional, morphological, optical and also the electrical properties of the solar cells were systematically studied. The results showed that the CTS thin films sulfurized at 580 °C would be a void-free and densely packed absorber layer with the grain size to be microns, having the band gap of ~ 1.01 eV. Furthermore, the sulfurization time is the key factor to influence the electronic properties of CTS absorber layer, and thus resulting in the best device performance of PCE = 2.41% by 20 min sulfurization process.