The stability of sensitivity of catalytic sensor was greatly improved by method of carbothermic. The sensor had nanobelts structure, moderate aperture and appropriate distributing of granularity after the process of carbothermic technique. The nanobelts structure of the sensor had even and stable distributing of catalyst on carrier, and the density and intensity of the carrier were higher and the ability of anti-sintering was greater than common sensor, so it would effectively prevent the attenuation of sensitivity of catalytic sensor in long-term working. The result of experiment showed that the sensitivity of catalytic sensor prepared by nanobelts attenuated only 7% in 30-day which was much better than 11% of common sensor.