Abstract:The diurnal variations in the rates of net photosynthesis and respiration of Camellia sinensis grown under different environmental conditions were measured with GH—Ⅱ analyser. The results revealed that the diurnal variation in Pn in the intercropping system on sunny days in spring and summer was in the shape of an monopeak curve pattern and the maximum value was 10.44mg CO_2·dm-2)·h-1. However, in the control (monocultural tea system) Pn showed a bipeak pattern and the maximum value was 8.36mgCO_2·dm-2h-1. The daily average of Pn was 7.35mgCO2·dm-2)·h-1 from April to July, which was 8.4% greater than that in the control. Light intensity was the most important ecological factor affecting Pn. The light saturation point of Pn was about 40—50 klx under natural condition. The rate of respiration of the leaves of C. sinensis was largely controlled by cemperatue. The temperature coefficient of respiration (Q(10)) was about 1.5, and the maximum temperature about 32℃. The daily average respiration inteneity was 4.39mgCO2·dm-2)·h-1, which was 14.0% less than that in the control.The daily average of transpiration rate of the leaves of C.sinensis was 4.04 g.g-1(FW), and 23.6% less than that in the control. It was greatly varied with the light intensity and temperature. In the intercropping tea plantation, the chlorophyll b content of the leaves and the ratlo of spongy tissue to palisade tissue were higher. The leaves of the tea trees in intercropping tea plantations are thinner and with less stomata. However, the content of chlorophll (a+b) and SLA were not greatly varied with shade. Therefore, it was demonstrated that Camellia sinensis is a light-demanding plant and has fairly shade-tolerant capacity.