Abstract: To address the demand for lightweight and high-strength ballistic materials in individual protection, this study investigates the strengthening mechanism of polyurea coatings on the ballistic resistance of spliced hexagonal SiC/UHMWPE fiber composite structures. Polyurea was coated on the ceramic front (PSU) and back (SPU) surfaces to form different composite targets. Ballistic tests and ABAQUS/Explicit simulations were used to analyze dynamic response, damage evolution, and energy dissipation under 7.62 mm armor-piercing projectile impact. Results show that polyurea significantly improves anti-penetration performance, with the SPU configuration superior to the PSU. This is because the SPU polyurea layer reflects tensile waves to alleviate stress concentration at the ceramic back surface, effectively captures ceramic fragments, and dissipates additional energy through its large deformation, thereby prolonging penetration time and optimizing the energy absorption path. Within 1–4 mm, ballistic resistance increases with polyurea thickness but tends to saturate beyond 4 mm. Increasing SiC thickness further enhances protection synergistically. The DSPU-4 configuration (8 mm SiC/4 mm polyurea/4 mm UHMWPE fiber) achieves the best performance, reducing back-face deformation by 81.5% compared with the baseline structure. This work provides theoretical and experimental support for designing lightweight composite ballistic structures.