Abstract: The samples of Volatile organic compounds (VOCs)from Platycladus orientalis were collected by the method of absorption thermodesorption, the physiological characteristics of the species were measured by Li-cor6400. The results showed: (1) There were 106 kinds of VOCs belonging to 9 classes in amount, the main VOCs of the P. orientalis in spring were terpenes. The VOCs beneficial to human being included terpene, ethyl acetate, decanal, and the harmful VOCs were chloroform, benzene, and toluene. (2) The total volatile organic compounds (TVOCs) concentration followed a "three peaks and two vales" pattern, the peaks were at 5:00, 13:00, and 19:00, and the vales were at 17:00 and 23:00—1:00. The appearance time of healthful components were at 5:00, 9:00, 15:00, and 19:00; the appearance time of unwholesome components were at 15:00, 21:00—1:00. (3) When the temperature was high, the illumination was strong, the humidity was low, the TVOCs concentration would be high, conversely, it would be low. The diurnal variation of transpiration rates, photosynthetic rates and the stomatal conductance were accorded with the concentration of TVOCs. It showed a very significantly positive relationship between the physiological characteristics and TVOCs concentration; a significantly positive relationship between the illumination and TVOCs concentration.