Effect of content and granularity of aluminum powder(Al)on the combustion characteristics and energy properties of casted CMDB propellants were studied,and the combustion mechanism was also investigated.Results show that energy of the CMDB propellant increases with the increasing of Al content,and optimal Al content is 8%.The burning rates of the CMDB propellant at lower pressures increase in a great extent when the proportion of common Al and nano Al is 1:1,and the burning rate exponents of the propellant under 7-15 MPa decrease to lower than 0.45.