The scarcity of materials with band gap value of 0.5~0.85 eV is one of the major challenges for the multi-junction solar cells. In this study, the compounds Cu2SnS3 with band gap of 0.83 eV is synthesized by non-vacuum mechanochemical method, and is prepared into absorber layer by non-vacuum printing technique. The photovoltaic properties of the Cu2SnS3 are studied by employing a superstrate solar cell structure of Mo/Cu2SnS3/In2S3/TiO2/FTO glass. Experiment result indicates that the short-circuit current density, open-circuit voltage, fill factor and conversion efficiency of the fabricated solar cell are 12.38 mA/cm2, 320 mV, 0.28% and 1.10%, respectively. Furthermore, to better meet the requirements of multi-junction solar cell on the current matching, the Cu2SnS3/In2S3 p-n junction of the fabricated solar cell is analyzed. A p-n modulation technique with a thin porous buffer layer inserted into the p-n junction interface is proposed. The results indicate that the technique can promote the short-circuit current density of the solar cell from initial 12.38 mA/cm2 to 23.15 mA/cm2, and the corresponding solar cell conversion efficiency from 1.1% to 1.92%. This p-n modulation technique can be an important reference to the printed thin film solar cells.