Abstract: In order to study the influence of deep cryogenic treatment on electrode wear in the spot welding of aluminum alloy,spot welding experiments are carried out by the non deep cryogenic treatment electrodes and the deep cryogenic treatment electrodes.The appearance of spot welds and the appearance of electrode tips are observed when the number of spot welds is 620 which is the non deep cryogenic treatment electrodes life.The micro-hardness of the deep cryogenic treatment electrode tips is tested when the number of spot welds is 620.The non deepcryogenic treatment electrode tips and the deep crogenic electrode tips are observed by X-ray diffraction.Experiment results show that the appearance of the non deep cryogenic treatment electrode tips changes sharply,but the appearance of the deep cryogenic treatment electrode tips changes little;the non treatment electrode pick up and the splash become worse than that of the deep cryogenic treatment electrode;the micro-hardness of the deep cryogenic treatment eleetrode tips is lower than that of the nontreatment electrode tips;the deep cryogenic treatment electrode wear is improved.