Multiple pore-loaded (1D) WO3 nanofibers (NFs) having 1D nanoneedle branches were successfully synthesized by polystyrenecolloid-template-assisted electrospinning followed by a two-step heat-treatment. Randomly branched WO3 nanoneedles and high porosity effectively facilitated the surface reaction with acetone molecules. In addition, the hierarchical porous WO3 NFs were further functionalized with catalytic non-oxidized graphene (NOGR) flakes, which showed dramatically improved acetone sensing performance. The results demonstrated the high potential for application in the diagnosis of diabetes by breath acetone analysis.