This research explores how outdoor spaces play a crucial role in providing urban children with opportunities for physical activity and relaxation, together with the supervision of the children’s outdoor activities, particularly in densely populated areas with limited open spaces. Effective design of such spaces is vital for creating functional recreational areas within urban landscapes. Drawing from ecological perceptual psychology’s theory of affordance, this research examines the positive attributes of environmental affordances, specifically in Beijing’s central area. Using a children’s park as a case study, systematic observations are conducted to understand the park’s potential for diverse play opportunities and facilitating social interactions across age groups. However, the results reveal that the children’s park falls short of realizing its affordances fully, restricting available play opportunities. Specific play activities require distinct spatial arrangements influenced by children’s ages. Maternal supervision significantly affects children’s play experiences. The study also highlights grandparent involvement in overseeing children’s outdoor play, revealing differing supervision styles. In conclusion, while fixed play equipment and rubber carpet ground enhance engagement and safety, realizing the complete potential of children’s outdoor play spaces demands more inclusive design. The research underscores the intricate interplay between environmental affordances, adult supervision patterns, and children’s play experiences, paving the way for further exploration of these dynamic relationships, and contribute to build environmentally and socially sustainable urban environments.