The invention belongs to the technical field of functional macromolecular materials and substance separation methods, and discloses a method for effectively removing molybdate ions in solution. According to the invention, by choosing one or more of dimethylaminoethyl methacrylate (DMAEMA), N-isopropyl acrylamide (N-IPAM) and acrylamide (AM) as monomers and one or two of sodium sulfate (Na2SO4) andsodium chloride (NaCl) as pore-forming agents, a macroporous cationic gel is synthesized by a free radical copolymerization method. The prepared macroporous gel is used for adsorbing molybdate in solution under certain temperature and pH. The method not only has a high adsorption rate and high exchange capacity, but also can completely remove molybdate ions in solution under appropriate conditions; according to the method, the stability is good, the reaction conditions are mild, the process is simple, the properties of the prepared gel material are good, and the method has a good applicationprospect in the fields of extraction and separation and controlled drug delivery and in the aspect of removing toxic anions in water environment.