Abstract: A series of polyoxyethylene macromonomer (PEO-A) with terminal acryloyl-groups have been synthesized from different molecular weight of polyethylene glycol and acrylchloride as raw materials via acyl-chloride method. Results show a better molar ratio n(PEG) : n(CH2CHCOCl) : n((CH3CH2)3N) is 2:1:1. Then the PEO-terminated groups non-ionic PAMAM dendrimers were prepared via Michael addition reaction of 96 h using PEO-A as the modifier for exterior terminal groups of PAMAM G1.0 ~ G4.0 dendrimers in the N2 atmosphere, 50 ℃ THF solution, respectively. The composition and structure of the modified dendrimers have been identified via FTIR, 1H NMR and 13C NMR.