3-Nitratomethyl-3-ethyloxetane was synthesized by the process of cyclization,nitation from trimethlolpropane and diethyl carbonate, and the homopolymer of 3-nitratomethyl-3-ethyloxetane was synthesized with 1,4-butanediol as initator and boron trifluoride etherate as an catalyst by cationic ring-opening polymerization. The effect of catalyst/initator molar ratio and reaction temperature on polymerization was discussed. The study of properties indicates that PNIMEO has a glass translation temperature of -25 ℃, the temperature decomposition of 218 ℃, the decomposition enthalpy of +1212 J·g^-1 , the explosion probability of 0, the 50% point of 109.6 cm.