Blue-light-emitting Si1-x Gex oxide nanowires have been grown on epitaxial Si0.8 Ge0.2 alloys on silicon by thermal annealing in a quartz tube furnace in N2 ambient. The photoluminescence spectrum of Si1-x Gex oxide nanostructures exhibits the blue-light emission with a peak at 415 nm, compared with the Si oxide nanowires with a peak at 470 nm. Nanowires with uncommon shapes, such as sunflowerlike and radiolarialike shape, have been observed. A field emission scanning electron microscope was used to monitor the growth of nanowires on the same patterned catalytic Au region. The growth can be understood in term of vapor-liquid-solid mechanism.