The energy,combustion properties and mechanical properties for the new designed smokeless cross-linked modified double-base propellant were thoroughly studied. Compared with ordinary double base propellant,the specific impulse for new designed smokeless cross-linked modified double base propellant was shown to be higher. The burning rate pressure exponents for the propellant compositions are about 0.34～0.50 in the range of 3～15 MPa.The tensile strength of the propellant is 0.64 MPa at 60 ℃ and the elongation is 94% at -40 ℃. The mechanical properties can meet the demands of case-bonded rocket motor.