Abstract: In view of the problem that gas concentration information in the detected signal of coal mine underground is weaker, the paper proposed a design scheme of gas detection system based on stochastic resonance. It analyzed principle of stochastic resonance, introduced structure of gas detection system based on multi-layer stochastic resonance algorithm, and gave simulation and numerical analysis by taking double-layer stochastic resonance model as example. The result showed that the system can be uninfluenced by underground noises and can get relatively accurate gas concentration information.