The vibration welding test of a 5 mm thick 5052 aluminum alloy is carried out by a fiber laser. The influences of joint microstructure and residual stress on the tensile properties and fatigue properties are studied. The research results show that the number of columnar crystals in the weld microstructure after vibration welding is significantly reduced, and the microstructure is more uniform and finer than that of an ordinary weld. Under the suitable vibration frequency and vibration acceleration, the residual stress of weld is decreased to 140 MPa, while that of an ordinary weld is up to 335 MPa. Under the tension-tension fatigue condition with a stress ratio of 0.1, the conditional fatigue limits of the base metal and joints are 160 MPa and 120 MPa, respectively. The fatigue source is located in the surface defects and the cracks propagate in a transgranular way. A large number of fatigue striations and secondary cracks are formed in the fractures.