Comparative study of WO3 thick film sensing features obtained by two different methods to ozone content in the air is presented. The thin films of 0.1-0.3 μ were obtained at evaporation temperature of 1100°C and pressure in chamber 1,33x10-8 bar. Films were formed by thick film technology from WO3 based paste. The films sensitivity to ozone is determined by working temperature of sensors. At the same time the characteristic stability depends on time and magnitude of temperature impulse. It was shown, that measurement sensor samples have high sensitivity to 70 ppb of ozone in the air.