Abstract: Aiming at the defects of wire gas monitoring mode at present,the paper proposed a design scheme of wireless sensor network system used in underground gas monitoring.It gave the network(structure) of the system,as well as introduced the design method of software and hardware of the system in details.The experiment result of simulating mine environment showed that the system improved security and stability of data,met design requirements of low-cost,low-power and low-complexity of coal mine safety system,which had a certain feasibility.