Deformation behavior in high-frequency fatigue failure of laser melting deposited Ti-6Al-2Zr-Mo-V alloys was investigated. The deformation modes and mechanisms were also discussed. The results indicate that the deformation behavior during fatigue crack nucleation and propagation are closely related to the dislocation motion and slip behavior. The fatigue cracks by slip deformation propagate along two slip planes. A lot of secondary cracks were observed on the crack propagation subsurface. Formation mechanism and effect of two types of secondary cracks were explained. Grain boundary deformation of coarse-columnar crystal was also discussed.