Abstract: Exposure of tomato plants to low temperature(10℃ and 5℃ )under low light(60tzmol／m²·s)results in a complete inhibition of plant growth，plant heights and the numbers of leaves ，and decreases the vigor of root and net photosynthetic rate．Compared with the plants before the treatment，the dry weight of shoot of treated plant is reduced，but the dry weight of root does not．During the recovery，the vigor of root，net photosynthetic rate，and the growth and development of plants under 10℃ treatment can recover completely．but those of plants under 5℃ treatment recover slowly except for the photosynthesis of developed 1eaves．