Abstract: The effects of microwave oven treatment on physiological activities and storage life of postharvest cherimoya (Annona squamosa) fruits were investigated. The results indicate that microwave treatments for 10～30 s decrease the fruit respiration rates and ethylene production, inhibit the activities of Pectic Enzyme(PE), Polygalacturonase(PG), and cell membrane permeability, and extend 1～3 days of the storage life. However, heat-injury associate with browning reaction appeared when fruits are treated for more than 30 s. Thus, a time of 20 s should be the optimum microwave treatment time.