The present invention relates to applications of a convection heat transfer method in a dianhydrodulcitol freeze drying process. According to the present invention, by using the convection heat transfer type freeze drying preparation method of the dianhydrodulcitol freeze drying powder, drying is performed according to the predetermined freeze-drying process to obtain the freeze drying product of the dianhydrodulcitol or the composition thereof, the melting point is high and is in the range of 99.5-103.5 DEG C, the time for achieving the complete freeze-drying state is short, the freeze drying product is the loose amorphous body, the melting point is not changed after the freeze drying product is stored for 200 days at a room temperature in a sealed manner, and the quality stability of the freeze drying product of the present invention is significantly superior to the quality stability of the dianhydrodulcitol freeze drying powder prepared in the prior art.