Abstract: When oranges are treated with ultraviolet radiation, their physiological parameters of peroxidase activity and physical parameters of electrical freguency characteristics, etc, change with the time of storage. The experimental result was analyzed. It showsed that a proper dosage of ultraviolet radiation can reduce the peroxidase activity, but kept the physical quantities of electrica freguency characteristics, etc., almost in the state of the beginning period of storage, and postponed the change of the internal structures and compositions of orange, thus, could keep it fresh.