The invention discloses subnaphthalocyanine acceptor materials, a synthesis method thereof and a solar cell, and belongs to the technical field of organic synthesis and photoelectricity. The synthesismethod comprises the steps: using a 6,7-dicyanonaphthalene monoimide compound and boron trichloride as raw materials, performing stirring for a reaction in an organic solvent at a certain temperatureso as to form chlorosubnaphthalocyanine triimide, and performing substitution on chlorosubnaphthalocyanine triimide by using fluoro groups, phenoxy groups or phenylthio groups so as to obtain a series of subnaphthalocyanine molecular acceptor materials finally. According to the design, imide groups are introduced into unsubstituted subnaphthalocyanine molecules so as to synthesize the new acceptor materials with good solubility, simple separation and purification and suitable LUMO energy levels. When the acceptor materials are applied to the bulk-phase heterojunction solar cell with simple requirements for a device structure, and the photoelectric conversion efficiency can reach 6.25%, which is the highest photoelectric conversion efficiency of inorganic solar cells which are treated through soluble solutions of subphthalocyanine, subphthalocyanine, phthalocyanine and naphthalocyanine.