As society develops, people pay more attention to the application of solar cell to harvest inexhaustible solar power, which has a benefit of greenness and cleanness. In this paper, we construct 14 heterostructures composed of g-C3N4 and Ⅲ-Ⅴ materials based on first-principles calculations. We systematically analyse their stability property and find a periodic rule of binding energy change about the atomic number of Ⅲ-Ⅴ material. We select 9 stable van der Waals (vdWs) heterostructures and further analyse their band alignment and power conversion efficiency (PCE). We find GaAs-D is a type-Ⅱ heterostructure with indirect band gap of 1.38 eV and the PCE reaches 15.2%. The construction of GaAs-D effectively promotes the optical absorption in visible-spectrum compared with two monolayers. This paper systematically analyses the stability of constructed vdWs heterostructures composed of g-C3N4 and Ⅲ-Ⅴ materials, electronic band structures and their potential application as solar cell.