The invention discloses a method for preparing a NiFe2O4/SnO2 compound photocatalyst. Firstly, SnCl4.5H2O and NaOH are dissolved in deionized water; then, NiFe2O4 nano-powder is added, and the mixture is stirred evenly; lastly, an obtained reactant is put into a hydrothermal kettle for a hydrothermal reaction, after the reaction is finished, cooling, washing and stoving are conducted, and then NiFe2O4/SnO2 compound photocatalyst nano-powder is obtained. According to the method, the surface of a NiFe2O4 octahedron is loaded with columnar SnO2, and NiFe2O4/SnO2 in an obtained product is a pure phase. Compared with the degradation rate of singular NiFe2O4 to methylene blue, the degradation rate of the NiFe2O4/SnO2 compound photocatalyst to methylene blue is increased by about 20%. The preparation technology is simple, needed equipment is simple, environmental friendliness is achieved, and industrial production is easily achieved. The method has the advantages that no secondary pollution is caused, and the product is easy to recycle. The NiFe2O4/SnO2 compound photocatalyst is environmentally friendly.