With diethylene glycol (DEG) and triethylene glycol (TEG) as starting materials, novel energetic plasticizers 1,5-diazido-3-oxopentane (AZDEGDN) and 1,8-diazido-3,6-dioxooctane (AZTEGDN) were synthesized via nitration and azidation reaction. The conditions of azidation reaction were optimized. And the structures were characterized by infrared spectra, magnetic resonance spectra and element analysis. Results show that the optimal reaction conditions for the synthesis of AZDEGDN are the molar ratio of sodium azide and DEGDN of 2.7∶1, the reaction temperature of 80 ℃,and the reaction time of 8 h, under which the yield of AZDEGDN is 96.4% and the purity is 99.1%.The optimal reaction conditions for the synthesis of AZTEGDN are the molar ratio of sodium azide and TEGDN of 2.5∶1, the reaction temperature of 75 ℃, and the reaction time of 8 h, under which the yield of AZTEGDN is 96% and the purity is 99.2%. In addition, the enthalpy of formation, the decomposition temperature, the friction sensitivity and impact sensitivity of AZDEGDN are 912.5 kJ·mol^-1, 249.3 ℃, 0% and 64.6 cm, respectively; while the main properties of AZTEGDN are 898.1 kJ·mol^-1, 256.1 ℃, 0% and 151.4 cm, respectively. However, both of their glass transition temperatures are less than -100 ℃.