A diffusionflame burner consisted of two coaxial tubes is designed and applied to studytheeffectof non-thermal plasmaonmethanediffusionflame. The basic phenomenon ofthemethanediffusionflame under dielectric barrier discharge assistance was observed. By adjusting the flow rate ofthemethane and air, the lifted height ofthemethaneflame and flame stabilization assisted by non-thermal plasma were studied in detail. Experimentalstudies have shown that, the presence of non-thermal plasma has a great impact onthe critical blow-off mass flow rate, flame lifted height, and flame stability characteristics. The active matters generated by dielectric barrier discharge have a limited life. When the position ofthe root oftheflame is far away from the non-thermal plasma zone or exceeds the moving distance ofthe active matters in the life period, theeffectof non-thermal plasmaonmethanediffusionflame will weaken or even disappear.