Abstract: In order to explore the microclimate regulation ability of street trees, with part of urban main roads in Chengdong New District of Zhaoqing City as the research object, the biological characteristics of street tree plant height, crown height and branch height were analyzed, and the regulation effect of temperature, humidity and solar radiation intensity was studied. RayMan Pro 3.1 is further used to calculate the thermal comfort index, based on which the thermal comfort is evaluated, and the correlation between street trees and thermal comfort and its influence on thermal comfort were analyzed. The results showed that the biological characteristics of tree species are closely related to tree shade ability and microclimatic regulation from the perspective of improving thermal comfort.Ficus microcapa, Khaya senegalensis, Mangifera persiciforma, Terminalia neotaliala and Artocarpus heterophyllus are good species for regulating microclimate. The street trees with tall trees and dense canopy can better play the shade performance and adjust the microclimate of road space, and effectively improve the thermal comfort level of pedestrians.