Air leakage has been an important factor affecting the energy consumption of sintering and pelletizing. The current available technology is not ideal to discharge sealing, such as star valve supply technology and double discharge valve technology. The cross-pressure differential discharge leakage is one of the main factors of the total leakage of sintering and pelletizing, accounted for about 10% of the total leakage of the sintering machine. Therefore, introducing the cross-pressure differential discharge leakage is of great significance to reduce the total energy consumption of sintering and pelletizing process. In this paper, the concept of cross-pressure differential discharge has been presented, the present situation and characteristics of cross-pressure differential discharge technology in sintering and pelletizing production are introduced; the split phase sealing technique to effectively solve the separation of pressure difference has been presented, the two-layer independent gas seal discharge valve and its application in sintering pellet based on split-phase sealing technique are introduced. The actual application data show that the overall air leakage rate of sintering machine can be reduced to 25%, which is significantly below the existing average leakage rate of 40% ~ 60%, proves this technology's great energy saving effect.