Abstract: The impacts of atomized chlorine dioxide(80 mg·L^-1 and 400 mg·L^-1) on the inhibitory effects of Alternaria alternata infections and fruits qualities of apples were studied by plate and puncture inoculation methods.Results showed that the lesion diameters of apples treated with atomized chlorine dioxide was lower than that of control group（treated with sterile water）. In addition, atomized chlorine dioxide treatments could slow down the decreasing rates of fruits firmness, soluble solid and titratable acid contents, and inhibit the MDA generatation.Meanwhile, the content of defensive materials（total phenols） and the activities of protective enzymes including POD,PPO and PAL were improved in atomized chlorine dioxide treated group. Consequently, the degradation of apple fruits qualities could be delayed after chlorine dioxide treatment in short storage, and atomized chlorine dioxide treatment with concentration of 80 mg·L^-1 showed better anticorrosion and fresh-keeping effects on apples fruits.