An experimental table was put up for the forced air pre-cooling test to cabbage. Five different modes of external openings were designed, including 28 holes, 32 non-uniform holes, 32 uniform holes, 40 holes and 50 holes. Forced air pre-cooling experiment was carried out respectively under the above different opening modes to cabbage and the temperatures of cabbage core and 1/2R were tested during the whole temperature-fall period, the cabbage core temperature uniformity after 6 hours pre-cooling was calculated. The results showed that: in preliminary stage, the external different opening modes had little effect on cabbage core and 1/2R temperature and all of the cooling rates were slow. However, with pre-cooling time increasing, the cooling rates speeded up and the gap between the cooling rates began to increase obviously. Of all the opeing modes, the temperatures of cabbage core and 1/2R decreased most quickly under the 40 holes external opening mode and through calculation, the cooling uniformity value of 40 holes external opening mde was the smallest and the cooling uniformity was the best. So the external opening mode of 40 holes in which the hole diameter is smaller at the bottom than the upper ones should be adopted firstly when doing forced air pre-cooling to vegetables and fruits.% 建立甘蓝差压预冷实验台，设计5种不同外部开孔方式，分别为28个孔、32个非均匀孔、32个均匀孔、40个孔和50个孔。分别对甘蓝在上述不同开孔方式下进行差压预冷实验，在降温过程中测试出甘蓝中心及1/2R处温度值，计算了甘蓝中心温度在预冷降温到6小时时的均匀性。结果表明：在初始阶段，周转箱外部不同开孔方式对甘蓝中心及1/2R处温度影响不大，且降温速度均较缓慢，但随预冷时间增加，降温速度逐渐加快且不同开孔方式下的降温速度之间开始有明显差距，其中外部开孔为40个孔的甘蓝中心温度和1/2R处温度均降低最快；另外通过计算知外部开孔为40个孔的降温均匀度最小，均匀性最好，故此种底部开孔孔径小，上部开孔孔径大的开孔方式在果蔬差压预冷应优先考虑采用。
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