Examining the spatial characteristics and accessibility of cultural facilities, such as art institutions, is crucial for understanding the lifestyles of citizens. With the increasing utilization of multi-source data in geographical studies, new opportunities have arisen for investigating the development of cultural facilities in urban areas. Consequently, this article investigates the spatial dynamics of art institutions in urban development, using Nanjing, a historic city, as a case study. The study obtained a total of 260,392 points of interest data for Nanjing in 2018 and 2022 from the GaoDe map API console. By employing network analysis and the two-step floating catchment area method, the geostatistical findings reveal that the distribution of art institutions in Nanjing has become more balanced over time. For instance, the research indicates that the proportion of residents able to reach art exchange institutions within a 30-min travel time increased from 75% in 2018 to 90% in 2022. However, the distribution of art training institutions remains more concentrated compared to art exchange institutions. Furthermore, the spatial arrangement of art institutions does not entirely align with the distribution of demand points, indicating the potential for further optimization. In conclusion, this study has significant implications for understanding the accessibility, social justice, and urban planning in Nanjing. The government should pay attention to the cultural demands of marginalized communities, promote social justice and cultural inclusiveness by increasing the accessibility of cultural facilities.