Abstract: The technology of drying by hot-air is widely used in practice because of its convenience. However, it has some defects such as the low efficiency and the inferior quality of the dried products, which becomes the obstacle of its further application. This study focuses on improving current technology. A new technology is introduced, that is, to dry bio-products by hot-air after they are pretreated by γ-irradiation. Experiments are made to study the influence of different dosages of irradiation, temperature of hot air, thickness of the slice apple on the rate of dehydration, temperature of irradiated apple. A conclusion is reached that the three-factors affect the rate of dehydration and temperature of slice apple. The more the dosage is, the greater the rate of dehydration of apple is, and the higher the temperature.