The main structure and electronic parameters of SnO2 thin films are considered from the point of view of optimization gas sensor characteristics. The results of phenomenological modeling and their comparison with experiments are used for choosing the correct film parameters and modes of deposition for the processing of SnO2 films by the spray pyrolysis method. Optimal deposition conditions were found, allowing one to obtain films with improved sensitivity, selectivity, low temperature sensitivity maximum position and low response times without additional doping by metal catalysts.