Thick films of bulk SnO2 and ZrO2 powders were observed as less sensitive to polluting, hazardous and inflammable gases. Hence, nanostructured SnO2 and ZrO2 powders were synthesized by disc type ultrasonicated microwave assisted centrifuge technique. Nanocomposite material, Zr(0.50)Sn(0.50)O4 was prepared using synthesized ZrO2 and SnO2 powders by taking their 1:1 proportion. Thick films of nanostructured pure Zr(0.50)Sn(0.50)O4 powder were fabricated by screen printing technique. These films were surface functionalized by Bi2O3 for different intervals of time followed by firing at 450oC for 30 min. The surface morphology, chemical composition, crystal structure of the unmodified and surface activated nanostructured Zr(0.50)Sn(0.50)O4 powder by Bi2O3 have been investigated by XRD, FESEM and E-DAX. Electrical and oxygen gas sensing performance of the thick films were also studied.