Abstract: To investigate the effect of shot peening coverage on residual stress distribution in shot peening strengthening, this study employs a FEM-DEM （finite element-discrete element method） coupling approach to transform shot peening process parameters and construct a discretized impact system. Numerical simulations of residual stress in compact tension （CT） specimens of FGH95 alloy under 100%, 200%, 300%, and 400% shot peening coverage were conducted. Results show that increasing coverage significantly enhances the amplitude and uniformity of residual compressive stress: at 200% coverage, the average residual stress increases by 13.4% and variance decreases by 35% compared to 100% coverage, indicating remarkable improvement in peening uniformity. Beyond 200% coverage, residual stress distribution tends to saturate, with the average stress increasing by less than 3.3% and variance stabilizing. Additionally, high coverage （400%） extends the thickness of the residual compressive stress layer to 0.63 mm, representing a 117% increase compared to 100% coverage. The study reveals the regulatory mechanism of shot peening coverage on residual stress amplitude, uniformity, and depth, providing a theoretical basis for optimizing shot peening process parameters.