Numerous metal oxide semiconductor materials were reported to be usable as semiconductor gas sensor, such as ZnO, SnO2, and TiO2 and so on. The samples of Zn and Cu doped SnO2 (SnZnO3 and SnCuO3) have been synthesized by solid-state reaction method. Some aspect of crystal structure of the compound at room temperature was studied using X-ray diffraction technique. The XRD study of the compound shows that there is a change in the basic crystal structure of SnO2 on substitutions of ZnO and CuO. The patterns of the SnO2 sample are indexed as tetragonal perovskite type with a = 7.3928 Å, c = 5.2879 Å but on substitution of ZnO and CuO the structure becomes orthorhombic with lattice constant a = 23.5237Å, b = 8.2183 Å and c =5.8017 Å or a = 21.8594 Å, b = 5.3200 Å, and c = 5.1803 Å, respectively. The temperature variation of resistance shows that compounds have negative temperature coefficient of resistance. The gas sensitivity for LPG (liquefied petroleum gas) showed a drastic change in conductivity.