Zinc oxide material is widely used in all photo electronic devices especially photovoltaics, in both organic and non organic solar cells. The present work focus on the study of the structural properties of tin doped zinc oxide ZnO:Sn and undoped zinc oxide ZnO deposited by spray pyrolysis technique. A variation in zinc acetate concentration has been made. Two values have been taken 0.4 mol/l and 0.5 mol/l. Doped zinc oxide layers have been realized by adding SnCl4 in the sprayed solution. After that, X-ray diffraction method have been carried out in order to determine the structural properties. For 0.4mol/l zinc acetate precursor concentration, a high cristallinity for tin doped zinc oxide layers is remarked compared to undoped ones, while in 0.5 mol/l zinc acetate the inverse occurs between doped and undoped layers.