Three-dimensionally　ordered　macroporous　(3DOM)　La0.6Sr0.4MnO3　(LSMO)　and　its　supported　gold　or　palladium　(xAu/3DOM　LSMO　or　yPd/3DOM　LSMO;　x　=　1.9-7.7　wt%,　y　=　0.4-1.4　wt%)　nanocatalysts　were　prepared　using　the　polymethyl　methacrylate-templating　and　polyvinyl　alcohol-protected　NaBH4　reduction　methods,　respectively.　The　LSMO　in　xAu/3DOM　LSMO　and　yPd/3DOM　LSMO　was　rhombohedral　in　crystal　structure　and　120-180　nm　in　pore　size,　and　Au　or　Pd　nanoparticles　(NPs)　with　a　size　of　3-4　nm　were　dispersed　on　the　surface　of　3DOM　LSMO.　In　each　serial　of　the　xAu/3DOM　LSMO　and　yPd/3DOM　LSMO　samples,　7.7Au/3DOM　LSMO　and　0.9Pd/3DOM　LSMO　performed　the　best,　giving　the　T-50%　and　T-90%　(temperatures　required　for　achieving　CO　conversions　of　50　and　90%,　respectively)　of　-9　and　50　degrees　C　and　84　and　120　degrees　C　for　CO　oxidation,　respectively.　It　is　concluded　that　the　high　surface　areas,　good　low-temperature　reducibility,　and　strong　interaction　between　noble　metal　NPs　and　3DOM　LSMO　were　responsible　for　the　excellent　catalytic　performance　of　7.7Au/3DOM　LSMO　and　0.9Pd/3DOM　LSMO.