Based on the sol-gel method, nanosized SnO2 material was prepared, and its structure and properties were studied by XRD, UV and Raman spectra. The XRD result indicated that the SnO2 particles had an ideal nanosize. The diameter of SnO2 particles increased with raising the temperature. The Raman spectrum indicated that the SnO2 nanometer material annealed at low temperature had a large number of O-empties. The UV spectra showed that the sample had stable absorption properties although the particle size changed greatly in the annealed range of 300-500 degrees C. These properties might be utilized in enhancing the performance of SnO2 gas-sensitive devices.