SiC–SiO2 core–shell fibers and 3C–SiC nanowires (nw-SiC) were grown on silicon nanoporous pillar array (Si-NPA) by thermal chemical vapor deposition method with nickel as the catalyst. The morphology, structure and composition of SiC–SiO2/Si-NPA and nw-SiC/Si-NPA were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Based on the experimental results a possible growth mechanism of nw-SiC was explained. Two broad photoluminescence peaks located at ∼409 and ∼494nm were observed both in SiC–SiO2/Si-NPA and nw-SiC/Si-NPA when they were excited utilizing 300nm fluorescent light at room temperature. The field-emission (FE) measurements showed that enhanced FE property was obtained in nw-SiC/Si-NPA. The excellent optical and field-emission performances of SiC–SiO2/Si-NPA and nw-SiC/Si-NPA were mainly attributed to the quantum confinement effects in nw-SiC and the nanometer-micron hierarchy structure of the composite systems.