Non-doped ZnO thin films are deposited on glass substrates by spray pyrolysis using diethylzinc solution at a range from a room temperature to 150 degrees C while making N-2 gas flow in atmospheric pressure. The morphology, the structural property, the density and the optical band gap are studied. As the deposition temperature is increasing, the overall density and the optical band gap approach to the values of ZnO single crystal. The quality of ZnO thin film deposited at 150 degrees C becomes near ZnO single crystal.