This study explores the design paradigm of public art in commercial pedestrian streets with Wangfujing Pedestrian Street as an example. Based on the spatial cognition theory, a mixed research method, including street observation, interception of visits, and behavioral map annotation, is comprehensively used to quantitatively analyze the interaction behavior and identity rating between tourists and public art, reveal the impact mechanism of public art on the overall spatial cognition of pedestrian streets through spatial layout, formal language, and symbol system. Based on this, the study starts from the logic of spatial perception and the aesthetic laws of design, optimizes the structure of the pedestrian street public space, constructs a "production, perception and ecology" trinity design paradigm, and emphasizes the synergistic coexistence of public art and commercial ecology, cultural inheritance, and environmental sustainability. This study innovatively applies the explanatory power of the spatial cognitive theory in the field of public art, providing a new theoretical perspective and practical guidance for the design of public art in commercial pedestrian streets.