Abstract: Studies were made of instantaneous transpiration rate and daily water consumption of 7 common garden species (Cinnamomum camphora, Osmanthus fragrans, Sapindus mukorossi, Koelreuteria integrifoliola, Celtis sinensis, Celtis biondi, Celtis julianae) under different weather conditions by use of Li-6400 portable photosynthesis system and ACS-D11 electronic balance and by adopting a pot experiment. The results showed that ① under the conditions of sufficient water, the changes tendency of water consumption rate of 7 tested species in different weather conditions were basically the same, lower in the morning and the evening, higher at around midday, displaying the unimodal or bimodal curve; ②The differences of daily water consumption under different weather conditions reached an extremely significant level, the differences of different tree species reached a significant level, among them the daily water consumption of Celtis biondii was extremely significantly higher than that of Cinnamomum camphora, and significantly higher than that of the other 5 tree species.