The escalating severity of the urban heat island (UHI) phenomenon and the occurrence of exceptionally high-temperature events have garnered increasing attention within the discipline of landscape architecture concerning how ecological design can effectively enhance urban microclimates and human thermal comfort. As a significant element of urban green space systems, bamboo forests exhibit considerable ecological regulatory potential; however, their microclimatic impacts and capacity to improve thermal comfort have not yet been comprehensively quantified. From the perspective of regulating services within ecosystem service frameworks, this study focuses on urban bamboo forests located in the northern section of the Sanlin wedge-shaped green space in Shanghai. Based on in situ observations conducted under high-temperature and high-humidity summer conditions, two composite thermal comfort indicators, Wet Bulb Globe Temperature (WBGT) and Heat Index (HI), were utilized to comprehensively evaluate the microclimate regulation effects of various bamboo species, namely Phyllostachys edulis, Phyllostachys vivax, and Phyllostachys viridis. Additionally, the study compares the differences between bamboo and non-bamboo communities, as well as between interior and edge spatial structures. The findings indicate that, in comparison to non-bamboo communities (including bare land, grassland, and mixed forest), bamboo stands notably decreased air temperature by 1.5~3.0°C and elevated relative humidity by 6%~10% during periods of midday heat, thereby effectively enhancing thermal comfort (with WBGT decreased by 2~3 units and HI decreased by approximately 3~4 units). Interior bamboo zones exhibited stronger microclimate regulation effects than edge zones, confirming the presence of an edge effect. Among the three bamboo species, P. viridis and P. edulis demonstrated the best performance. Their dense canopy structure, high Leaf Area Index (LAI: 3.7~4.1), and low gap fraction (≤22%) significantly enhanced microclimate regulation (e.g., WBGT reduction by 2~3 units and humidity increase by over 6%). In contrast, P. vivax showed weaker regulatory ability, likely due to its lower leaf area index and higher canopy light penetration. This study provides a scientific foundation and practical reference for optimizing bamboo resource allocation in urban afforestation projects and for the high-efficiency design of ecological services in future urban green spaces.