The carbon nano-tubes/potassium perchlorate (CNTs/KClO₄) composite was prepared via a double decomposition reaction of NH4ClO₄ solution and KOH solution in the presence of carbon nano-tubes. Morphology character and thermal behavior of the composite were studied by scanning electron microscope （SEM), transmission electron microscope (TEM), differential scanning calorimeter (DSC) and specific surface area (SSA) analyses. Results show that KClO₄ prepared by this method is coated on the surface of CNTs effectively. In comparion with pure CNTs, the diameter of CNTs supporting KClO₄ increases significantly and the SSA of the CNTs/KClO₄ composite decreases by 40.719 m²·g^-1. In comparion with KClO4, the thermal decomposition temperature of the composite decreases by 75 ℃ and crystal transformation peak temperature decrease by 5 ℃. In comparion with Mo/KClO₄, the thermal conductivity of Mo/KClO₄ ignition composition prepared by CNTs/KClO₄ increases by 33.9％.