The gas sensors based on tungsten oxide (WO 3 ) thin films and doped with different amount of gold (Au) or palladium (Pd) were synthesized by a new developed preparation system using the pulsed Nd:YAG (532nm) laser deposition method combined with dc sputtering. The crystalline structure and crystallographic orientation of the prepared Au doped WO 3 (WO 3 -Au) thin films, measured by X-ray diffraction system, suggested that there were distinct peaks of WO 3 (001) and (201) and weak peaks of WO 3 (120), (111), (002) and (112). The maximum sensitivity for 200ppm NO 2 were approximately 69 for WO 3 -Au thin film and 24 for WO 3 -Pd thin film at the operating temperature of 300 o C, respectively. These maximum sensitivities are higher than that of the non-doped WO 3 sensor which sensitivity is about 17. This may be due to its electronic and/or chemical sensitization effect.