Pervoskyte nanocrystalline ZnSnO3 thin films were prepared by spray pyrolysis technique. Nonocrystalline ZnSnO3 thin films were characterized by different analytical technique exhibits X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. Prepared sensor showed a better sensitivity (S ~ 91) at operating temperature of 300 °C for 500 ppm to H2 gas with the short response (5 sec.) and quick recovery times (13 sec.), respectively. The results are discussed and interpreted.