Abstract: The fatigue crack propagation rate, fatigue fracture morphology and microstructure in base metal, fusion line, weld center and heat affected zone of TA2 titanium alloy welded joint were studied. The results show that the fatigue crack propagation rates in different zones of the joint had small difference and thus could be directly presented by the crack propagation rate of the weld zone. The fracture of samples from different zones illustrated typical fatigue fracture morphology. The average grain size of the base metal was about 62.8 μm, and that of the heat affected zone was about 110 μm. The grain size had little influence on the fatigue crack propagation rate.