This study is grounded in the learning and interpretation of heterotopic space theory, offering a comprehensive analysis of heterogeneous spaces in contemporary cities from both physical and social dimensions. The research focuses on outdoor urban environments, excluding typical heterotopias that are driven by singular functions. When addressing architectural spaces, particular attention is given to how building façades shape the adjacent streets and squares as part of the public realm. Through methods including literature review, case analysis, and field investigation, the study traces the conceptual development and analytical approaches of heterogeneous space, deepening the understanding of this theory through four interpretive lenses: "Space locality," "subjective presence," "nodes within the network," and "interactive online presence." On this theoretical basis, the research further proposes the application of heterogeneity as a design strategy to enhance urban diversity and distinctiveness.