Abstract: The methane alarm device based on SMT32F103RBT6 central processing chip of Cortex-M3 core not only has performance such as the accurate detection of underground environment methane concentration, concentration overrun real-time alarm, real-time detection of data storage performance, but also has protection function to prolong sensing element lifetime and prevent impact damage in case of high concentration methane, reduce the failure rate. The portable methane alarm device can be well applied in mine environments.