In order to expand the quick-frozen method of food， the method of quick freezing fresh jujube slices by liquid air spray was proposed. The model of liquid air spray quick freezing tank was established by COMSOL Multiphysics. The velocity field and temperature field of fresh jujube slices were simulated， and the temperature changes of fresh jujube slices at different times were obtained by field probes and boundary probes during the quick freezing process. By comparing the quick freezing effects of different liquid air injection speeds (0.02， 0.04， 0.06， 0.08， 0.1 and 0.2 m/s)， it is concluded that the time of fresh jujube slices to meet the quick freezing requirements decreases with the increase of flow rate. When the flow rate is 0.06 m/s， the freezing rate is faster and the cold energy is used more fully. The quick freezing tank models with five outlet positions (lower right， upper right， directly above， upper left and lower left) were established. The results show that the model with the outlet in the upper left can realize the quick freezing of fresh jujube slices more efficiently and the temperature distribution of fresh jujube slices is more uniform. Compared with the existing cryogenic liquid nitrogen tunnel quick freezing， the liquid air spray quick freezing has a shorter time to meet the requirements of quick freezing， and has outstanding advantages in heat transfer and energy saving.