The chemical heat pump using the reversible reactions of NH₃ and notal chlorides is being expected to wide applications like the alternative refrigeration and cooling system and effective energy managements. The distinguishing characteristics of this system is utililization of the expanded graphite as a support in the chemical reactor to overcome the deactivation of reaction and improve the heat and mass transfer of reactive medium. In contrast with ordinary reaction block of uniform properties such as apparent density and ratio of expanded graphite, the on-uniform reaction block was designated to increase the apparent density with radial direction, which is able to improve heat transfer properties and solve the troubles which the permeability of ammonia gas get worse while increasing heat transfer. Based on the experimental results, the rate of reaction of the non-uniform block is progressed rapidly and has larger thermal conductivity in the heat transfer zone than the uniform blocks. Additionally the non-uniform blocks are proved to have betterment of reactivity for the decompositive reaction.