The prepolymer polyurethanes(PUs)based on isophorone diisocyanate(IPDI),poly(propylene glycol)(PPG),1,4-butanedioi(BDO)and dimethylopropionic acid(DMPA)were synthesized at 75-80℃ for 7-8 hours,using dibutyltin dilauate(DBTDL)as catalyzer,and polyturethane-acrylate hybrid emulsion was prepared after methyl methacrylate(MMA)was polymerized,using potassium persulfate and azobisisobutyronitrile(AIBN)as initiator,respectively.The influences of these factors such as the kind of initiator,the feed method of initiator and the addition of initiator on properties of polyurethane-acrylate were studied.The FTIR and GPC of aqueous polyurethane were analyzed.The FTIR spectra show that the degree of microphase-separate between the soft segments and rigid segments is high.The analysis of molecular weights stated that molecular weights increased most significantly after amine was added.The experimental results reveal that the appearance of emulsion is excellent,the film is harder and the water absorption radio of the film is less when oil-solubility AIBN is used as initiator.The semi-continuous can increase the molecular weight of polymer and the optimum amount of the initiator was 3% for MMA.