Abstract: Foam metal is a new type of material which can inhibit gas explosion flame and pressure wave. But its isola- tion performance is unpredictable under the environment of coal dust. To research the influence regulation of foam met- al’s isolation on gas explosion flame after adding coal dust with different parameters in pipe,the experiment was car- ried out in a gas explosion transfer device designed by ourselves and its diameter is 120 mm. The results show that the attenuation rate of gas flame wave were 92. 95% ,97. 93% ,80. 95% ,and 92. 05% respectively after adding 5 g, 10 g,50 g,and 100 g coal dust with particle sizes of 60 -80 mesh. For the foam metal with specific parameters,the quality of coal powder can reduce the barrier performance in a certain range. In comparing the attenuation rates of foam metal,the closer to the foam metal’ s aperture the dust particle size was,the more likely stranded in barrier material the dust was,and even worse the barrier effect of the foam metal would be. Its attenuation rate was falling to 68. 23%when 100 g coal dust (40-60 mesh) added. The study found that the quality and particle size of coal dust in pipe can make important influence on foam metal’s blocking performance.