A new nanostructure, (2D) nanopetal of SnO2, has been grown on single silicon substrates by Au-Ag alloying catalyst assisted carbothermal evaporation of SnO2. Field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD) and Raman are employed to identify the morphology and structure of the synthesized productions. Room-temperature photoluminescence (PL) is used to characterize the luminescence of SnO2 nanostructure. Three new peaks at 356, 450 and 489 nm in the measured photoluminescence spectra are observed, implying that more luminescence centers exist in SnO2 nanopetals due to nanocrystals and defects. The growth of the SnO2 nanopetals is discussed on the basis of the self-catalyst mechanism.