In order to enhance the energy-release efficiency of aluminum powder， the inert alumina layer of micron-sized aluminum was replaced by cobalt layer with higher thermal conductivity via combining the replacement and subsequent electroless plating methods. Thus the Al@Co core-shell particles were obtained. The cobalt shell thickness was respectively confirmed as 90， 150， 200 and 250 nm. Scanning electron microscopy， transmission electron microscopy， energy dispersion spectrum， vibrating-sample magnetometer， and thermal tests were conducted. The results show that the cobalt shell is dense and uniform with controllable thickness， and the natural oxidation resistance of the particles rises with the increasing shell thickness. And the particles exhibit typical ferrohysteresis loops， further confirming the presence of ferromagnetic cobalt. Al@Co core-shell particle with 200 nm-cobalt coating can fully overcome the endotherm resulting from the melting of aluminum， showing sharp exothermic with the enthalpy energy of 521.40 J·g^-1， which is a promising selection of fuel component in novel green primary explosives.