Based on safety and high efficiency of dry powder fire extinguishing device with non-pressure storage, basic formulas with different oxidizer ratios were designed for the gasproducing grains. Burning rate under different oxygen differences was compared, the residue was analyzed by XRD test, and the gas production was also compared. The results show that oxidant content has a great influence on burning rate and gas production, so oxygen consumption of the oxidant should be considered when oxygen difference is designed. Too much residue after combustion will reduce performances. In order to seek stable burning rate and low residue, the best oxygen difference should be controlled to be around －15 to－20. In the optimal basic formula, mass fractions of oxidizer, combustible agent, and binder are 77.2%, 11.4%, and 11.4%, respectively. When oxygen difference is －15, burning rate is 8.95 g/s, and gas production is 0.245 L/g. Compared to a firefighting grain, the gas production increases by 19%.