The tungsten oxide（WO3）gas sensor which is heater type are prepared by dopping with carbon nanotube（CNT）.Ball milling and ultrasonic dispersion are used to disperse CNT

SEM is used to identify the WO3fine powders which prepared by sol-gel techniques

and the gas sensing properties of sensor is researched.The result shows carbon nanotubes exist in the WO3 grain which average particle size is about 30

5

0 nm

thus increasing the porosity of materials.CNT-WO3gas sensor is more sensitive to acetone than pure WO3sensor

and quality fraction 0.4 % is the optimal degree of adulteration for sensing to acetone

and it is good at low volume fraction

high selectivity

fast response.