Controlling the microstructure morphology after deformation in the β single-phase region is crucial for the service performance of near-β titanium alloys. The microstructural evolution of the TC18 titanium alloy after hot deformation in the β single-phase region was investigated. The results show that as the strain rate decreases, the fraction of low-angle grain boundaries (LAGBs) significantly decreases, the serrated β grain boundaries tend to straighten, and subgrains expand from grain boundary regions into grain interiors with noticeable coarsening. The grain orientation analysis reveals that with decreasing strain rate and increasing deformation, the volume fraction of the {001} texture significantly increases, whereas the {111} texture exhibits the opposite trend. This is attributed to the synergistic effect of preferential activation of the {112}<111> slip system and strain-induced grain boundary migration (SIBM). Additionally, lower strain rates lead to an increase in the dynamic recrystallization (DRX) fraction, with the DRX mechanism transitioning from discontinuous dynamic recrystallization (DDRX) to continuous dynamic recrystallization (CDRX), which also enhances the {001} recrystallization texture component.