Abstract: Due to the easy firing of the catalytic elements in the gas sensor, the activity reduction and poisoning, the rare-earth elements were tried to modify the C atalytic elements of the gas sensor.A test was conducted on the special surface area, activity and stability of the n-Ce-Zr-AI203 catalyst mixed with rare-earth double gr oup components and the n-AI2O3 common nano catalyst. The test results showed that the catalytic elements of the mixed Ce-Zr co-catalyst, the reaction activity was ob viously improved, the working temperature of the methane with the volume fraction of 1% could be reduced by 40 °C than the common catalytic elements and the reacti on stability was obviously improved.The gas catalytic elements was inserted into the test module for the error test. The test showed that under methane with volume frac tion of 1% ~ 5%, the max measuring error was about 3%, far below than the national standard and was fully met with the gas detection requirements.