The influence of prior cold deformation after solution treatment on the α phase precipitation behavior during the subsequent aging treatment and final mechanical properties of TB3(Ti-10Mo-8V-1Fe-3.5Al) alloys was investigated. In the predeformed samples, network patterns were observed after aging treatment by metallographic microscope. Transmission electron microscopic (TEM) observation shows that in the predeformed-aged samples, the plate-shaped α precipitates prefer to nucleate and grow in high density dislocation sites, such as grain boundaries and slip bands. In addition, variant selection effects were observed in these samples. Results of X-ray diffraction and metallographic microscope indicate that α phase precipitation process could be accelerated in predeformed samples. Tensile test results reveal that by cold deformation the aging time could be shortened and the tensile strength could be enhanced, while the ductility could be reduced, in comparison with the freely aged sample.