The properties of N-guanylurea dinitramide (FOX-12) have been studied. FOX-12 is dissoluble in cold water. It has a crystal density of 1.755 g/cm³,the heat of combustion 1 483.98 kJ/mol,the temperature of decomposition 218.41℃,low sensitivity and good thermal stability. FOX-12 can be compatible with the common energetic materials,such as HMX,RDX etc.