The ternary semiconductor Cu3BiS3, as a promising light-absorber material for thin film solar cells, was creatively synthesized by sulfurizing the mixed metal oxides precursor film deposited by spin-coating chemical solution method. Two kinds of sulfurization techniques were introduced to study the effect of the sulfur concentration on the phase formation for the pure Cu3BiS3. It was found that Cu-poor S-rich phases such as Cu3Bi3S7 and Cu4Bi4S9 were easily generated at high S concentration and then can transform to Cu3BiS3 phase by a simple desulphurization process, which means the sulfur concentration had a significant influence on the formation of Cu3BiS3 during the sulfurization process. The probable transformation mechanism from the mixed metal oxides to the pure Cu3BiS3 phase during the sulfurization process was studied in detail through the XRD analysis and thermodynamic calculation. In addition, the electrical properties were characterized by Hall measurement and the effects of sulfurization temperature on the phase transformation, morphology and optical band gap of the absorber layer were also studied in detail. (C) 2016 Published by Elsevier B.V.