Hydrothermal　method　synthesis　of　α-MnO2　nanowires　has　been　achieved　at　different　temperatures　in　this　work.　X-ray　diffraction　and　transmission　electron　microscopy　confirmed　the　pure　phase　of　the　α-MnO2　nanowires.　All　of　the　samples　crystallized　in　a　single-phase　nanowires　shape.　The　α-MnO2　nanowires　diameter　increased　from　11　nm　to　21　nm　with　the　increase　in　hydrothermal　temperature　from　120　C　to　200　C.　The　α-MnO2　catalytic　activity　on　the　decomposition　of　ammonium　perchlorate　(AP)　was　characterized　through　thermogravimetric　analysis.　The　decomposition　rate　of　AP　with　the　addition　of　α-MnO2　was　size　relative.　The　11　nm　MnO2　nanowires　exhibited　the　best　catalytic　activity,　which　lowered　the　high-temperature　peak　of　AP　by　130°C.　©　2013　Elsevier　Ltd.　All　rights　reserved.