A novel poly (ethylene glycol) grafted 4-dimethylaminopyridine dicationic functionalized ionic liquid ([DMAP-PEG1000-DIL][BF4]) was synthesized with water-soluble polymer poly (ethylene glycol) as raw material. Its structure and thermal stability were characterized by 1HNMR, 13CNMR, FTIR, ESI-MS and TGA. A series of 4H-chromen-4-yl-phosphonates in yields of 83%~94% were prepared by one-pot, three-component reactions of different substituted salicylaldehyde with malononitrile and triethyl phosphite in water under the conditions of [DMAP-PEG1000-DIL][BF4] dosage being 10 mol% different substituted salicylaldehyde and reaction temperature 100℃. This reaction used water as solvent and the catalyst could be reused for five times, which met the basic requirements of green chemistry.