The forced-air precooling experiments of apples were carried out to study the influences of temperature, relative humidity and velocity of the cold air, and the void ratio of apples on the precooling process. The results show that the optimum operation velocity for the apples cooling is 1.5m/s.Well cooling effect of apples can be obtained with low temperature (4℃, no chilling injury) and high humidity air (80% RH above) in air circulation. The void ratio of apples has little influence on the precooling time when the air velocity is greater than 1.5m/s, 〖and the increase of the void ratio will significantly reduce the precooling time when the air velocity is less than 0.75m/s. 