Methane is an important greenhouse gas, which is less in the atmosphere, but grows rapidly, and become the second most important greenhouse gas after CO2, methane is 28 times more ef?cient per mass as a greenhouse gas than CO2, It has a radiative forcing of, 0.5 ± 0.05 Wm?2, about 28% that of non-CO2 atmospheric constituents in 2010. If this situation develops without limitless, it will bring unprecedented disaster to the Earth's ecological environment. At the same time, methane is also an extremely important source of energy. It is the main energy source (about 88% portion) of the natural gas and the natural gas hydrate (about 99% portion) in the deep sea contain several times more of the sum amount of natural gas resources in the world, with China's economy showing high speed, blowout growth, conventional energy and new energy exploration has become an important task of our country. At present, the coal industry occupies 66% portion of China's energy consumption structure, with the expansion of coal mining scale, coal mine accidents (gas explosion) will occur frequently, the methane gas concentration (major portion of the gas) signal will play more and more important role as the gas explosion warning. Therefore, the development of high precision in situ methane sensor is of great significance for greenhouse treatment and conventional natural gas exploration, mining, transportation and natural gas hydrate and other new energy exploration. As the target environment is relatively complex (more water vapor, CO2 and other miscellaneous gas), by comparing the different types of methane gas sensor and found that other types of methane sensors have a certain application restrictions, and solid-state electrolyte mixed potential methane sensors can adapt to such environments perfectly. Therefore, this paper uses solid-state electrolyte mixed potential methane sensor to carry out experimental research. By comparing the SEM images of YSZ ceramic sheets made by tape-casting method, slip-casting method and tableting method, it is found that the YSZ ceramic prepared by the tableting method has many surface pores after sintering under the special temperature program, is the ideal way of making solid state electrolyte. Combination with related literature, we create a novel tubular-type methane sensor, the baseline and output voltage value of tubular-type methane sensor is more stable compare with planar-type methane sensor, but the tubular-type methane sensor is more fragile that can’t conduct repetitive experiment, and the output voltage value below the planar-type methane sensor, after the comprehensive consideration, we chose planar-type methane sensor to do this research. The impedance spectra and the polarization curves of the methane sensor with SnO2 as the working electrode were tested. The sensor with the oxide as the working electrode was in accordance with the mixed potential mechanism perfectly. It is also found that the methane sensor with In2O3 as the working electrode has excellent sensing performance, and the performance is still superior in the 6% water vapor environment, which is in accordance with the reality environment. We fabricate a novel sensor which use noble metal as sensing electrode, and the output voltage value is more stable compare with oxide sensing electrode, and it’s also show superior gas sensitivity in the hydrothermal environment.