The one-off air pressure has great influence on the running efficiency and product quality of construction waste crusher. At present, the various air flue runners all need sufficient one-off air pressure to make sure the one-off air has relatively high outlet air speed which is conducive to the mixing of the coal powder s and the one-off air and to the absorption of the second-time air and form recycling flame. The higher the one-off air pressure is, the bigger the resistance that the blower needs to overcome will be, which has higher requirement for the performance of the blower and the electricity consumed by the blower will be higher, so that it is necessary to reasonably adjust the one-off air pressure. No matter what type of blower, change the air amount, the air pressure will be changed. As for the question of how to coordinate them both, we need to not only be careful when choosing the suitable type of blower, take full consideration on the types of raw coal and the stability of the coal sources and the output and size of the kiln, but have a good knowledge on the relationship of one-off air amount and air pressure in the detailed operation and adjustment process. The adjustment principle of the one-off air pressure is that the one-off air amount is not high and the change of the one-off air pressure is not great. As for this requirement, using frequency conversion technology control motor and adjusting the air speed through the frequency conversion are the most reasonable, which not only is energy saving, but has few changes on the property curve of the blower. At present the most widely used method for adjusting the air amount is that using inlet air door to control the centrifugal fan and outlet air to control the Roots blower. The result of this control is that while the air amount is changed, the change of the air pressure will be greater. In the practice, even though the value on the one-off draft indicator can remain unchanged, this value only means that the static pressure stays the same, the dynamic pressure of the gas greatly drops with the decreasing of the air amount, which means, the one-off air speed which brings power to the flame decreases and the burning speed of the coal powers will slow down. For this reason, though using frequency changer will increase the one-off investment, it will bring high benefits.