The utility model relates to a self-diagnosis carbon monoxide sensor for a coal mine. According to the self-diagnosis carbon monoxide sensor, an intrinsic safety power supply in an intrinsic safety casing is electrically connected with a battery conversion module and then electrically connected with a central processing unit, and the intrinsic safety power supply is further sequentially and electrically connected with a power supply conversion module, a carbon monoxide detection circuit and the central processing unit; the power supply conversion module is further electrically connected with an output port reuse circuit; the battery conversion module is electrically connected with the power supply conversion module; and the central processing unit is further in infrared connection with an infrared remote control unit and electrically connected with a display unit respectively. The self-diagnosis carbon monoxide sensor is characterized in that the central processing unit is electrically connected with and controls an output port reuse circuit of an RS485 communication module, a frequency output end and a current output end. The self-diagnosis carbon monoxide sensor realizes integration of multi-system output communication modes, simultaneously realizes self-diagnosis of open circuit, short circuit and communication signal failure states of current type, frequency type and RS485 bus type output circuits, and realizes self-diagnosis of a carbon monoxide element and information transmission.