In this study, we introduce a simple and effective seed-mediated growth method (SMGM) for the controlled synthesis of boron suboxide powder. By employing starting powders with different concentrations and adding boron suboxide seeds with a star-like morphology, we demonstrate that B6O ceramics that exhibit high-level crystallinity can be synthesized using SMGM at ambient pressure conditions. The formation of multilayered star-shaped B6O particles via SMGM is reported for the first time.