To effectively monitor methane concentration in the underground, for interference large characteristics underground , combined with real-time monitoring for methane concentration requirements, self-eliminate vibration optical structure was designed with rectangular prism linked, and the real-time data communication system was constructed based on the wireless network. In interferometer system, the position of two rectangular prism were fixed. The two beam splitters with connecting rod so that it can rotate synchronously, and the optical path difference is generated by rotation. As a result of the link structure, the vibration introduced into the two beam splitters are present in equal amounts at any time. Because the results was calculated used the difference value, therefore, it can be completely destructive effect. By analyzing the maximum range of rotation of beam splitter, the optical path difference range of the system can be calculated. Then through Beer-Lambert law, methane gas concentration detection limit of the system was given in the underground. Experiment in the laboratory and in the main mine roadway were completed, the measured standard concentration of methane gas obtained through a chemical reaction, and the results was compared to test results of WQF530 type spectrum analyzer. The results show that under the conditions of non-interference in the laboratory, the relative error of two detection methods were less than 1.0%;In the underground experiments, the test results of conventional optical detection methods significantly affected by the environment, and relative error was greatly increased, but the test results of the system was stable. So it is strong anti-interference ability and stability.