Abstract: At present,there are a large number of methane transport pipelines. Once the gas drainage pipes leak or are affected by external fire,it is likely to cause an explosion accident. Based on the self-built inert gas / ultra-fine water mist inerting suppressing test system on gas explosion,this paper carried out a series of gas-explosion inhibition experi-ments on 9. 5% methane / air explosion by gas-liquid two-phase medium. The synergistic inhibition law of gas-liquid two-phase medium on 9. 5% methane / air explosion was obtained,and the reason of synergistic effect of explosion sup-pression was analyzed,and the study proposed the inter phase coupling effect between gas-liquid two-phase medium. Results showed that under the combination of CO2 ,N2 ,He and Ar four inert gases and ultra-fine water mist,the inhibi-tion effect on overpressure,flame propagation speed and the maximum flame temperature was obviously improved. When the dilution fraction of four inert gases reached 14% and the amount of ultra-fine water mist reached 8. 4 mL (mass concentration 694. 4 g / m3 ),the gas-liquid two-phase medium had a good inhibition effect on 9. 5% methane /air explosion. While the controlling parameters continued to increase,the growth rate of explosion suppression effect gradually reduced. The synergistic explosion suppression effect of CO2 and ultra-fine water mist was the best,N2 was the second,and He and Ar were the least. However,the synergistic explosion suppression level of the combination of He,Ar and ultra-fine water mist had little difference,which provides a scientific support for the clean and efficient de-velopment and utilization of inerting water mist explosion inhibition technology.