The leakage flow fields and pressure distributions of the twostage brush seal were investigated based on a twodimensional closed staggered tube bundle model of the bristle pack cross section that was solved using computational fluid dynamics (CFD).The effect of number of stages and clearances between stages on the average outlet axis velocity and the effect of pressure ratio and number of up and down stage axial bristle rows on the interstage imbalance of pressure drops were analyzed.The results show that interstage imbalance of pressure drops is existed in two stage brush seals when the number of up stage axial bristle rows equals to the down stage and pressure drops of the down stage are larger than that of the up stage,the whole pressure drops will increase the interstage imbalance of pressure drops.The leakage is decreased with the increasing of the number of stage and the leakage reduction tends to be slow when the stage number is greater than three.Increasing the up stage axial bristle rows and decreasing the down stage ones can improve the interstage imbalance of pressure drops.