This study aims to explore the relationship between plant thermal regulation effects and their leaf traits and architecture traits, in order to provide a scientific basis for selecting plants for enhanced thermal regulation effects in urban green spaces. The study focused on 24 common deciduous broad-leaved tree species in Beijing, such as Populus tomentosa, Sophora japonica, and Prunus persica 'Duplex’. It involved measuring leaf traits like leaf thickness and leaf mass per area, as well as architectural traits including plant height and crown height-to-width ratio. Additionally, the Li-6400XT Portable Photosynthesis System and the Li-250A Light Meter were utilized to determine indices such as plant transpiration rate and solar radiation intensity beneath the canopy. Based on these measurements, heat regulation indices like heat absorption and solar radiation reduction rate were calculated. The study analyzed the relationship between these indices and the relevant traits of different tree species. Significant differences (P < 0.05) were found in the transpiration heat absorption and solar radiation interception capabilities among the 24 greening tree species. Overall, tree and small tree life forms showed better thermal regulation effects than shrubs. In particular, Fraxinus pennsylvanica and Acer truncatum demonstrated strongly comprehensive thermal regulation capabilities. Besides these two species, Populus tomentosa and Koelreuteria paniculata excelled in transpiration heat absorption per unit land area, while Ginkgo biloba and Sophora japonica performed well in intercepting solar radiation. Syringa oblata showed weaker comprehensive thermal regulation effects. The leaf transpiration heat absorption ability was significantly positively correlated with leaf dry matter content and leaf mass per area (P < 0.05), and plants with greater height and higher tree height-to-width ratio had stronger transpiration heat absorption capacity. Leaf area index and crown height-to-width ratio significantly influenced the plant's ability to intercept solar radiation (P < 0.05). Fraxinus pennsylvanica and Acer truncatum possessed superior thermal regulation effects. Leaf dry matter content, leaf mass per area, and architecture traits such as plant height, under-branch height, and tree height-to-width ratio wereimportant indicators affecting the thermal regulation effects of greening tree species.