The invention discloses a synthesis method of a SnS2/Mn3O4 three-dimensional multilevel structure and an obtained product. The synthesis method comprises the following steps: mixing a tin salt, thioacetamide, p-phenylenediamine and absolute ethyl alcohol to obtain a transparent solution, enabling the transparent solution to have a solvothermal reaction, and obtaining a SnS2 flower-like self-assembly body; dispersing the SnS2 flower-like self-assembly body into mixed solvents of water and glycerin, adding PVP, a manganese salt and sodium acetate, mixing evenly to obtain a mixed solution; enabling the mixed solution to have a solvothermal reaction, and obtaining the product. A morphology controllable SnS2/Mn3O4 composite is obtained through the two steps of solvothermal reactions. The SnS2/Mn3O4 three-dimensional multilevel structure is novel in microstructure and controllable in size, the reaction process is easy to regulate, the product uniformity is good, the repeatability is high, and the SnS2/Mn3O4 three-dimensional multilevel structure has a higher application value in the field of photocatalysis.