In presented work the influence of microstructure and shape factor of zinc oxide active layer on sensing parameters of resistive chlorine gas sensor is described. Three sensors were made using different methods of sensitive layer fabrication: screen printing and chemical bath deposition, with and without presence of electric field. Obtained results show that choice of fabrication method has a significant influence on electrical and sensing properties of designed sensors. Performed SEM measurements indicate that by using CBD method a q-1D ZnO structures were synthesized. THS studies have shown that the smaller zinc oxide structures have the higher conductivity and better chlorine sensitivity.