This study investigates the effects of shot peening intensity, shot medium (cast steel shot and ceramic shot), and composite shot peening on the fatigue properties of high-strength and high-toughness β-titanium alloy. Characterization techniques, including scanning electron microscopy (SEM) and X-ray diffractometry (XRD), were employed to analyze the influence of shot peening processes on the surface integrity and fatigue fracture behavior of target materials. Experimental results show that shot peening effectively modifies the machined surface profile of target materials. With the increase of shot peening intensity (up to 0.25 mmA), surface roughness increases, yet no delamination or micro-crack defects are observed, indicating excellent plasticity toughness of the target materials. However, the surface of target materials is sensitive to coverage: Local delamination and wrinkling defects occur on the surface after composite shot peening with 400% coverage. Shot peening introduces a residual compressive stress layer approximately 280 μm in depth on the surface of target materials. The residual stress value generally increases with shot peening intensity, but stress relaxation occurs in the near-surface layer (50 μm thickness) when the intensity reaches 0.22 mmA. Shot peening significantly enhances fatigue performance: Under cast steel shot peening conditions, the fatigue life increases by 145.4 times compared to the as-received state, with individual specimens reaching 1×107 cycles. Ceramic shot peening demonstrates more pronounced fatigue improvement at the same intensity. For peening with a single-shot medium, crack initiation sites shift to the subsurface layer, whereas composite shot peening reduces the average fatigue life significantly, with some crack sources appearing on the surface, attributed to surface damage and residual stress relaxation. In conclusion, high-strength and high-toughness β-titanium alloy exhibits favorable shot peening performance, low sensitivity to shot peening intensity (resistant to delamination or microcrack), but high sensitivity to shot peening coverage, making it unsuitable for composite or extended shot peening treatments.