Abstract: The photosynthetic rate under different CO_2 concentration condition was measured during the growth stage of Camellia sinensis from March to July in 2004. The results showed that: when the temperature was above 34.0℃ and PAR reached about 800μmol m~(-2)s~(-1), the decreasing speed of photosynthetic rate due to high temperature became slow by enhancing the atmospheric CO_2 concentration. And the inhibited temperature enhances approximately 1～2℃ or 3～4℃ when the CO_2 concentration was 550ppm or 700ppm. Under a weak light (the PAR was below 400μmol m~(-2)s~(-1)) condition, although increasing CO_2 concentration could improve the photosynthesis rate, the effect of air temperature on the photosynthesis rate was more obvious. At this light condition, the most suitable temperature was 29.0～30.0℃, the photosynthesis rate would weaken even stop if the temperature exceed 30.0℃ or 34.0℃.

Key words: Camellia sinensis, Camellia sinensis, Photosynthetic rate, CO_2 concentration