To address the failure caused by surface corrosion fatigue of titanium alloy structural components and to extend the service life of titanium alloys used in aircraft structures, supersonic fine particle bombardment (SFPB) technology was applied to the hot-rolled Ti-6.5Al-2Zr-1Mo-1V (TA15) alloy with varying impact durations. This process created a gradient nanostructure on the surface of the samples, and various instruments and equipment were used to study the effects on the microstructure, microscopic morphology, and mechanical properties after different treatment time. Results show that when the SFPB treatment time is 60 s, the surface average nanocrystal grain size of the hot-rolled structure is minimized, measuring 30.4 nm. The surface roughness of the treated samples increases compared to the original ones, and the minimum surface roughness is obtained after treatment for 60 s. However, longer impact times leads to the formation of microcracks on the sample surface. The SFPB treatment introduces high compressive residual stress on the sample surface, resulting in a significant increase in microhardness. After the SFPB treatment, the strength increases, with a slight decrease in elongation before stabilizing. With treatment time of 60 s, the best combination of strength and plasticity is achieved. The corrosion fatigue life of the SFPB-treated sample is improved by 12.7 times compared to the untreated sample. The SFPB treatment is able to generate a gradient nanolayer near the surface of the TA15 titanium alloy, significantly enhancing its tensile properties and corrosion fatigue life.