Silica-based ceramics are widely used in radome applications due to their excellent dielectric properties and thermal stability. However, traditional ceramic forming techniques face significant challenges in fabricating components with complex geometries. To improve the forming quality and mechanical properties of silica ceramics, this study employs Digital Light Processing (DLP)-based additive manufacturing to investigate the effects of different reinforcement phases. Using photosensitive resin as the matrix, composite ceramic samples are prepared by incorporating mullite particles, aluminum nitride particles, and alumina-coated particles as reinforcements. The phase composition, microstructure, bulk density, and flexural strength of the samples are systematically characterized. The results indicate that the type of reinforcement significantly affects the crystallization behavior of cristobalite and the densification process of the ceramics. Among all reinforcements, mullite particles yield the best overall performance, with vertical and horizontal shrinkage rates of 8.73% and 8.66%, open porosity of 17.44%, a bulk density of 1.80 g/cm³, and a maximum flexural strength of 17.94 MPa.