<p>With the rapid development of additive manufacturing technology, 3D printing technology has been gradually applied to the preparation of silica ceramic cores, which provides more possibilities for the development of aero-engine hollow blades to more complex and finer design directions. However, in the practical application process, 3D-printed silica ceramic cores are facing severe challenges. Especially at the typical 1350&#xa0;°C application temperature of aero-engine, the flexural strength is low, which is difficult to meet the requirements of hollow blade investment casting process. In this study, three different concentrations of titanium oxide (TiO₂ impregnation) and yttrium oxide (Y₂O₃ impregnation) impregnation solutions were used to analyze the effects of types of sols and concentrations on the microstructure and flexural strength of 3D-printed silica ceramics. The results show that the flexural strength of 3D-printed silica ceramics was effectively enhanced after impregnation with TiO₂ impregnation and Y₂O₃ impregnation. Among them, the 10% yttria sol impregnation significantly improved the mechanical properties of the samples, which was 1.79 times that of the untreated silica ceramics. Scanning electron microscopy observation showed that the SiO₂ ceramic core impregnated with 10% Y₂O₃ impregnation solution had fewer cracks and pores, and the flexural strength was the best and showed the best comprehensive performance: open porosity of 20.0 ± 0.5%, bulk density of 1.92 ± 0.07&#xa0;g/cm³, and flexural strength of 10.78 ± 0.30&#xa0;MPa.</p>