The influence on the performance of nitramine modified double base propellant with KE(a nitrite) and K₂SO₄ as eliminated-flame additive was investigated.By using burning rate test, differential scanning calorimetry(DSC), rocket engine test and an infrared thermal imaging device, the influence mechanism was discussed.Results show that the KE has the fewer influence on the heat of thermal decomposition and combustion characteristics, and better effect on suppression after burning of propellants than K₂SO₄.In addition, thermal decomposition characteristics of NC/NG and RDX in propellants are affecteded obviously by KE.