In present work is reported the zinc oxide (ZnO) deposit on corning glass substrates at 400°C by sol-gel spin coating technique. The optical effect of ZnO films was analyzed by transmittance measurements taken with help of UV-vis spectrophotometer. All the films showed transmittance ˃85% in visible range. Gas sensing measurements were taken in presence of CO2 at 300°C with a concentration of 1000ppm. Results revealed sensitivities above 50% in presence of CO2.