<p>This study introduces a novel sandwich-structured composite incorporating varying contents of zirconium diboride (ZrB₂), with polybenzimidazole (PBI) as the resin matrix and quartz fiber felt (QF) as the reinforcement. The ablative performance of the composites was assessed under high-energy continuous wave laser conditions, featuring a laser power density of 30 MW m^-2, and the laser ablation morphology and ablation mechanism of the ZrB₂/PBI/QF composites were investigated. Further analysis examined the effects of ZrB₂ ceramic content on the density, thermal stability, mechanical properties, ablation characteristics, and rear surface temperature of the composites. Upon laser ablation, ZrB₂ oxidizes, forming a protective white ZrO₂ layer. At a 60% ZrB₂ content, the rear surface temperature of the composites reached 1031 °C after 42 s, resulting in a low linear ablation rate (0.12 mm s^-1). The gases and residual carbon produced by the pyrolysis of PBI resin, the melting of QF, and the release of SiO₂ gas contribute to the formation of a SiO₂ protective layer. Building on this foundation, the incorporation of ZrB₂ further enhances energy dissipation and facilitates the development of a ZrO₂-SiO₂ protective layer with increased reflectivity. This layer, along with another oxidation product, B₂O₃ gas, serves to isolate oxygen and mitigate erosion. The findings suggest significant potential for developing advanced materials for high-energy continuous wave laser protection.</p>