Abstract: To study the flow state in the wake region of a randomly packed structure and the flame characteristics of premixed gas burning on its surface, a new randomly packed structure wake burner and a visual experimental device were designed. The influence of inlet flow rate on the surface flow field of randomly packed structure and the combustion and emission characteristics of methane/air premixed gas on its surface were studied. The results show that the air flow increases by 20 L/min, the overall average velocity of the unreacted flow field increases, and the vorticity and strain rate increase by about 50%. The average axial velocity near the packed bed surface is high and the fluctuation is violent, while the fluctuation far from the packed bed reduce and tends to be uniform.The effect of equivalent ratio on velocity distribution is significant, but its effect on flame propagation is relatively attenuate.Under experimental conditions. The content of CO in flue gas reaches the lowest value when the air flow rate is 50 L/min and the equivalent ratio is 0.91. The experimental results have a certain guiding role for the development of porous media surface burner.