Tin dioxide (SnO2) nanoparticles have been synthesized in bulk quantity by thermal evaporation of SnO powder. The x-ray powder diffraction (XRD) analysis indicates that the nanoparticles are the tetragonal rutile structure of SnO2. Scanning electron microscopy (SEM) analysis shows that the size of the synthesized SnO2 nanoparticles is relatively homogeneous with diameter of about 10 nm. Gas-sensing components have been manufactured with the SiO2 nanoparticles. Their performances indicate that it has high sensitivity and selectivity to LPG, and the max sensitivity appears at 280°C, compared with C2H5OH, H2, CO and CH4.