<p>In this study, hot-rolled TA15 titanium alloy was used as the initial research material. The TA15 titanium alloy was subjected to laser shock peening (LSP) to create a gradient nanostructure in the near-surface layer of the specimens. A comparative study was conducted on the microstructure, surface integrity, mechanical properties, and corrosion resistance of the TA15 titanium alloy before and after LSP treatment, utilizing various testing and characterization methods. The strengthening mechanisms by which LSP enhances the performance of the TA15 titanium alloy were investigated. After LSP treatment, the near-surface of the TA15 titanium alloy specimens underwent severe plastic deformation, generating a high density of structural defects such as dislocations. Through the dislocation subdivision mechanism, the grain size on the surface of the hot-rolled specimens was refined to the nanoscale. The surface roughness of the treated specimens was reduced, and the surface microhardness increased by 16.2%, reaching 403.6&#xa0;HV. The maximum residual compressive stress of − 306&#xa0;MPa was observed on the outermost surface of the specimens. The synergistic effect of multiple factors, including grain refinement, residual compressive stress formation, increased dislocation density, and twin generation, led to improved tensile properties<Emphasis Type="Underline">.</Emphasis> The grain refinement and the introduction of residual compressive stress accelerated the formation of the passive film and decreased the corrosion current density from 84.03 to 12.11&#xa0;nA/cm². Consequently, the corrosion rate of the TA15 titanium alloy was reduced, and its corrosion resistance was significantly improved.</p>