The sub-eutectoid U-Nb alloy tube was spun with reduction ratio of 15% at room temperature. The samples sectioned from the spun tube were annealed at 700, 655 and 600 ℃ in the vacuum for 1 h, respectively. The effects of cold-spinning and different temperature annealing on the microstructure evolution were studied by means of optical metallography(OM), scanning electron microscopy(SEM) and X-ray diffraction (XRD). The results indicate that cold-spinning deformation can refine the initial microstructure by mechanical breaking. The alloy after different-temperature annealing had different α+γ binary phase pealite microstructure, i.e. particle-like at 600 ℃, layer-like at 655 ℃ and stick-like at 700 ℃.