Objective To study the effect of spraying micro-arc oxidation on the corrosion fatigue life of aluminum alloy TIG welded joints, in order to provide an effective method for prolonging the life of welded joints. Methods The 5083 aluminum alloy was welded using TIG welding, the microstructure of the welded joint was observed, and the micro-hardness distribution of welded joints with the distance from the weld center was tested. The growth curve and cross-section nano-hardness of the ceramic coating were investigated after spraying MAO treatment. Under the three loading conditions with the max-stress of 7 kN,8 kN,9 kN, the tensile fatigue test was conducted for welded samples treated by micro arc-oxidation and the untreated samples after 168 h of pre-corrosion, and the fatigue life of the two samples was compared. Results The surface state of welded joints of aluminum alloy was not uniform, whereas the ceramic coating of joint showed good uniformity after micro-arc oxidation. The increment in thickness of the ceramic layer was first fast and then slow, and the surface roughness showed a nearly linear positive correlation with the thickness. Under the three loading conditions (7,8,9 kN), the fatigue life of the untreated welded joints decreased by 50. 7% ,58. 3% ,64. 9% respectively, compared with those after spraying micro-arc oxidation treatment. Conclusion The surface condition of TIG welded joints could be improved by spraying micro-arc oxidation, which blocked the erosion of weld substrate by corrosive medium, and improved the fatigue life of aluminum alloy and equipment parts under corrosion and alternating stress.