<p>As a reliable additive manufacturing technology, the stereolithography (SLA) ceramic core necessitates a tailored sintering process to achieve optimal performance. This study explored the effects of final sintering temperatures (specifically 1,150, 1,250, and 1,300 °C) on the properties of SLA-fabricated SiO₂-based ceramic cores reinforced with nano-ZrO₂ (at concentrations of 1.0wt.%, 1.5wt.%, and 2.0wt.%). The results demonstrate that increasing the final sintering temperature and the incorporation of nano-ZrO₂ enhance the viscous flow of quartz glass, resulting in a higher sintering degree. As the final sintering temperature rises, the ceramic samples exhibit increased shrinkage rate, decreased apparent porosity, and increased bulk density. Higher final sintering temperatures also promote greater cristobalite precipitation, promoting an increase in the amount and precipitation rate of quartz during investment casting. The formation of a cristobalite and ZrSiO₄ network at elevated temperatures effectively inhibits the viscous flow of quartz glass, thereby significantly improving high-temperature flexural strength and creep resistance of ceramic cores. When the content of nano-ZrO₂ is between 1.5wt.% and 2.0wt.%, the final sintering temperature of 1,250 °C is the best choice. Under these conditions, the shrinkage rate along the Z direction ranges from 3.35% to 3.68%, the porosity lies between 25.57% and 26.03%, the bulk density varies from 1.612 to 1.645 g·cm⁻³, the room temperature flexural strength is between 26.79 and 27.85 MPa, and the flexural strength at high temperatures is within the range of 30.77 to 33.02 MPa. The deflection at high-temperatures is 3.37–5.31 mm, while the surface roughness of the upper surface is 3.26–4.79 μm, and the surface roughness of the side surface is 4.97–5.79 μm. These findings provide valuable guidance for optimizing the sintering processes of SLA ceramic cores, offering potential for industrial applications.</p>