As urbanization advances and lifestyles evolve, public demand for high-quality green spaces that meet cultural and spiritual needs has been consistently rising. Waterfront green spaces, serving as a form of urban open space, not only deliver ecological benefi ts but also provide aesthetic, social, and other intangible values. The perception of cultural ecosystem services (CES) has emerged as a crucial indicator for assessing the value of urban green spaces. Nevertheless, current research remains limited in identifying the characteristics and drivers of such perceptions. A data-driven quantitative framework is urgently required to improve explanatory capacity. This study, focusing on 47 waterfront green spaces along Shanghai’s “One River and One Creek”, develops a CES perception assessment model utilizing social media text comments. Using Jieba word segmentation and Baidu’s sentiment analysis for emotional feature extraction, coupled with LightGBM for modeling and SHAP for interpretation, the research systematically identifi es key landscape elements infl uencing public perceptions and their mechanisms. The fi ndings show that: (1) The public generally holds a positive view of cultural services in waterfront green spaces, but signifi cant spatial diff erences exist. Comments related to recreation and aesthetic appreciation are the most frequent, while those related to artistic inspiration and science education are relatively less common; (2) Elements such as built structures, water features, and pets are identifi ed as strong positive drivers, enhancing aesthetic appreciation, emotional value, and social activities. Recreational facilities, trees, terrain, and stones show neutral eff ects, whereas certain public amenities may negatively aff ect perception. This study establishes an interpretable evaluation framework based on social media data, off ering a new perspective for understanding public responses to CES in urban green spaces and providing theoretical and methodological support for the refi ned planning and management of waterfront landscapes.