Nitrogen　oxide　(NOx)　emissions　have　attracted　much　attention　for　increasing　concern　on　the　quality　of　the　atmospheric　environment.　In　view　of　NO　decomposition　in　the　cement　production　process,　the　preparation　of　Cu-Al/SiO2　porous　material　and　its　effect　on　NO　decomposition　were　studied,　and　the　denitrification　mechanism　was　proposed　in　this　paper.　The　NO　decomposition　performance　of　the　Cu-Al/SiO2　porous　material　was　tested　via　the　experimental　setup　and　infrared　spectrometer　and　micro　gas　chromatography　(GC).　The　result　shows　that　the　Cu-Al/SiO2　porous　material　with　the　template　of　cetyltrimethylammonium　bromide　(CTAB)　had　a　better　NO　decomposition　rate　than　materials　with　other　templates　when　the　temperature　was　above　500　degrees　C,　and　NO　decomposition　rate　could　approach　100%　at　high　temperatures　above　750　degrees　C.　Structure　analysis　indicates　that　the　prepared　Cu-Al/SiO2　material　structure　was　a　mesoporous　structure.　The　X-Ray　Diffraction　(XRD)　and　Ultraviolet-visible　spectrophotometry　(UV-Vis)　results　of　the　denitrification　product　show　that　the　Cu-Al/SiO2　material　mainly　decomposed　to　Cu2O　and　Si2O,　and　the　CuO　decomposed　to　Cu2O　and　O-2　at　high　temperature.　The　Cu(I)O　was　considered　as　the　active　phase.　The　redox　process　between　Cu(II)O　and　Cu(I)O　was　thought　to　be　the　denitrification　mechanism　of　the　Cu-Al/SiO2　porous　material.