The invention relates to SERS-based magnetic test paper for detecting nitrite as well as a preparation method and a use method thereof. The magnetic test paper comprises a super-hydrophobic film, goldnanorods and a magnetic composite, wherein the gold nanorods are erected on the surface of the super-hydrophobic film in bundles after self-assembling; the magnetic composite is entrained among the gold nanorods. The gold nanorods and the magnetic composite are self-assembled on the surface of the super-hydrophobic material to form the magnetic test paper with excellent SERS property. 4-amino thiophenol adsorbed on the surface of the magnetic test paper is coupled with to-be-detected nitrite, and an SERS signal of a coupling product is utilized, so that quantitative and qualitative detectionon the nitrite is conducted indirectly. The magnetic test paper prepared by the method is corrosion-resistant and staining-resistant, has excellent SERS property and magnetism, is convenient to carry,can be rapidly separated out of a complex system under the action of an external magnet, and has wide application prospect in on-site, rapid and high-sensitivity detection on the nitrite in complex samples such as food, environments and biological samples.