In this work the photovoltaic properties of InxGa1-xN/SnS and AlxGa1-xN/SnS heterojunction solar cells are studied by numerical analysis. The photovoltaic performances of InxGa1-xN/SnS solar cells are enhanced with the decreasing In content and the GaN/SnS solar cell exhibits the highest efficiency. The efficiencies of GaN/SnS solar cell improve with the increased SnS thickness and the reduced GaN thickness. For the AlxGa1-xN/SnS solar cells, there is electron barrier in the AlxGa1-xN/SnS interface. The electron barrier becomes larger with increasing Al content and lead to the degraded efficiency of AlxGa1-xN/SnS solar cells. The simulation contributes to designing and fabricating SnS solar cells. (C) 2016 Elsevier Ltd. All rights reserved.