<p>Sustainable Development Goal 11.7 (SDG 11.7) is used to evaluate urban sustainability from the perspective of public spaces. The deepening of urban sustainability accompanies an urbanization process characterized primarily by land expansion. However, current research on the relationship between land expansion and SDG 11.7 faces issues such as mismatched indicators and an inability to reveal the internal spatial differences in this relationship. Therefore, this study uses Xi’an as a case example—a rapidly developing city facing significant urban challenges. First, it monitors the spatiotemporal dynamics of SDG 11.7 in Xi’an. Secondly, from a spatial perspective, it focuses on whether the continuously expanding urban land can effectively promote SDG 11.7 levels, as well as on the spatial disparities and balance issues associated with this promotion within the city. The findings indicate that: (i) SDG 11.7 levels in Xi’an have increased annually, transitioning from an initial single-core center to a multi-core spatial pattern. (ii) New expansion areas can effectively drive the growth of SDG 11.7, although their driving capabilities vary across different regions. (iii) While these new expansion areas provide momentum for urban development, they also tend to create regional imbalances. This study conducts a comprehensive spatiotemporal assessment of SDG 11.7 in Xi’an, and addresses the shortcomings of previous research on the relationship between SDG 11.7 and land expansion, providing scientific evidence for policymakers to promote rational land expansion and enhance urban sustainability.</p>