The flow characteristics of multi-jes in the same direction and in great velocitydifference in combustion chamber were researched by the cold mould simulating test of self-designedlow- calorie value gas burner.The results showed that the large negative pressure region and back-flow region would be produced by the multi-annular jets with high-velocity air involve intensivelythe central low-velocity gas jet and by virtue of the small main air volume resulting by some extentcirculation of gas jet.These have the advantage of realising homogeneously mixing between air jetsand gas jet and combusting steadily.