Abstract: In order to study the effect of organophosphorus dimethyl methylphosphonate ester on coal spontaneous combustion characteristics, select the Doren lignite coal sample as the experimental coal sample, and thermogravimetric experiments were carried out using the combination of temperature-gas chromatograph and STA-449C synchronous thermal analyzer. The calculation model of the volume fraction generated by CO and the temperature of coal body in the process of simulating the spontaneous combustion heating of coal by comparing four kinds of resistance agents with different concentrations was studied. The activation energy was obtained by fitting, and the flame retardant effects of different concentrations of flame retardants were analyzed by combining the results of thermogravimetric experiments. The results show that the CO release rate of coal samples with 20% dimethyl methylphosphonate ester is the minimum during the heating process, and in the process of coal spontaneous combustion, the best inhibiting effect on coal is achieved. Moreover, E value of activation energy of the inhibitor with a concentration of 20% was the largest, with the best inhibiting effect and the most difficult spontaneous combustion.