Abstract: In order to quantitatively explore the characteristics of transpiration water consumption and functions of cooling and humidification for the typical urban greening tree species in summer, we selectedseventeen main greening tree species in Shanghai and measured their transpiration characteristics by using LI-6400 photosynthetic apparatus. The correlation between transpiration and the main influencing factors was analyzed, and the functions of cooling and humidification were estimated quantitatively by clustering analysis. The results showed that:1) The daily variation of transpiration rate showed a pattern of “low in the morning and evening but high around noon, presenting unimodal or bimodal distribution.Ilexchinensis,Zelkova schneideriana, andMagnolia albahad a high mean daily transpiration rate, whileMagnolia grandiflora,Koelreuteria paniculata,Distylium racemosum, and Michelia maudiaehad a muchlower value. 2) Except for a very few tree species, the transpiration rate had a positive correlation with net photosynthetic rate, stomatal conductance, leaf temperature, solar radiati on, air temperature, etc.3) In terms of the capacity of daily cooling and humidifying per unit of land area,Ilex chinensis and Cinnamomum camphora were the higher, while that of Koelreuteria paniculata,Ginkgo biloba,Micheliamaudiae,Distylium racemosum,Elaeocarpus decipiens,Magnolia grand if lorawere relatively lower.When it comes to selecting tree species considering the capacity of cooling and humidifying,Ilexchinensis,Cinnamomum camphora,Magnolia alba,Sapindus mukorossi,Zelkova schneideriana,Liriodendron chinense,Platanusspp.,Acer buergerianum,Bischofia polycarpa,Osmanthus fragrans,Photinia serrulataoutperform others such as Koelreuteria paniculata,Ginkgo biloba,Michelia maudiae Distylium racemosum,Elaeocarpus decipien sand Magnolia grandiflora.