Abstract: Aiming at the disadvantage that voice alarming in existing comprehensive monitoring and control system of coal mine only had simple sound but no concrete voice prompting,the paper introduced a voice alarming circuit,which was designed with ISD2590 voice chip.Taking application of the circuit in some methane sensor as example,the paper introduced its hardware and software design.The result of field trail running showed validity and reliability of the circuit.The circuit is also suitable for other sensors in comprehensive monitoring and control system of coal mine.