The invention discloses a preparation method of a cerium-titanium composite oxide low-temperature SCR catalyst and belongs to the technical field of catalyst preparation. The preparation method particularly includes: placing a cerium precursor, an organic ligand, a carrier TiO2 and a small amount of organic solvent into a ball milling tank for ball milling to obtain well-mixed powder; calcining to obtain the CeO2-TiO2 composite oxide catalyst, wherein content of cerium oxide is 5-90wt%. Within a temperature range of 200-400 DEG C, NO conversion ratio of the catalyst is maintained higher than 95%. The preparation process is simple, preparation conditions are easy to control, and the preparation method is environment-friendly.