We propose a new route for transferring catalysts onto macroporous metal oxide nanofibers (NFs) using metallic nanoparticles (NPs) infiltrated block copolymer microparticles as sacrificial templates. Pt decorated polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) copolymer microparticles (Pt-BCP MPs), produced from oil-in-water emulsions, were uniformly dispersed within electrospun PVP/W precursor composite NFs. The macropore-loaded WO3 NFs (macroporous Pt-WO3 NFs), which are additionally functionalized by Pt NPs (10 nm), were achieved by decomposition of polymeric components and oxidization of W precursor after high-temperature calcination. In particular, macropores with the similar size distribution (50300 nm) with BCP MPs were also formed on interior and exterior of WO3 NFs. Chemical sensing performance of macroporous Pt-WO3 NFs was investigated for pattern recognition of simulated breath gas components at highly humid ambient (95% RH). The result revealed that superior hydrogen sulfide sensitivity (R-air/R-gas = 834.2 +/- 20.1 at S ppm) and noticeable selectivity were achieved. In addition, H2S pattern recognition against other chemical components (acetone, toluene, and methyl mercaptan) was clearly identified without any overlapping of each pattern. This work demonstrates the potential application of BCP-templated maroporous Pt-WO3 NFs in exhaled breath analysis for noninvasive monitoring of physical conditions.