Noise pollution significantly impacts people’s health and quality of life,while urban green spaces not only beautify the environment but also play a crucial role in noise reduction and sound absorption.This study,using the plant communities of waterfront green spaces along Suzhou Creek in Shanghai as a case,innovatively develops a comprehensive evaluation system for physical and psychological noise reduction effectiveness,with 13 indicators.Through field measurements and surveys of 14 urban green spaces with different plant community characteristics,the study found that physical noise reduction effectiveness is closely related to plant species richness and vertical canopy density.Densely planted trees with thick trunks and tall shrubs significantly improve physical noise reduction effectiveness.When the vertical canopy density is less than 35%,the physical noise reduction effectiveness of waterfront plant communities(with 70%vegetation cover and 30%water cover)outperforms that of terrestrial plant communities(with no water cover)at the same canopy density level.For psychological noise reduction,increasing shrub crown width,height,and spacing improves visual perception,while enhancing vertical canopy density enriches auditory perception-both of which raise the auditory annoyance threshold.The most effective plant community combination for comprehensive noise reduction is a mix of densely planted trees,shrubs,and ground cover.The noise reduction effectiveness of a waterfront plant community is impacted by vertical canopy density.When it reaches 40%or more,the psychological noise reduction effectiveness will improve as the density increases.This study provides theoretical support and practical guidance for addressing noise issues in urban green spaces and optimizing plant community configurations.