The effects of annealing temperature and annealing times on the tensile properties of TA15 titanium alloy specimens with high Mo equivalent and large deformation were studied. The results indicated that the recovery and recrystallization softening play the leading role, the precipitation strengthening of the metastable results in the strength rise with the annealing temperature increasing, and the re-fall is caused by the coarsening of the secondary α phase and the reduction of the proportion of the primary α phase. Repeated annealing at 800 ℃ does not decrease more than 10 MPa for the tensile strength of the specimen. The plasticity is basically unchanged, and the microstructure and properties are kept to be nearly stable. It can be drawn that repeated annealing has no obvious adverse effect on the properties of the semi-finished product.