Dimethyl methylphosphonate (DMMP), which acted as the simulant of nerve warfare agents, was degraded by strong ionization discharge gas. Experimental results show that DMMP could be degraded rapidly by the strong ionization discharge gas, and the total organic carbon of the solution decreased significantly. Moreover, the free radical accelerant and inhibitors significantly influenced the degradation efficiencies of DMMP. Free radicals were the most important oxidants for the DMMP degradation reaction in this system. Hydroxyl radical could attack CH₃—P, P—OCH₃ and O—CH₃ groups of DMMP to start a degradation reaction. The analysis of byproducts indicated that phosphate esters, methyl phosphoric acid, and CO₂ etc. were formed after the treatment. Furthermore, DMMP would be probably mineralized. Finally, four reaction pathways were predicted for the DMMP degradation by the strong ionization discharge gas.

Key words: strong ionization discharge, nerve warfare agent, simulant, DMMP, mechanism study