Taking open -air tea garden, greenhouse tea garden covered with ordinary agricultural film as control, studied physiological and ecological effects of greenhouse tea garden covered with light conversion film and supplement of CO_2 gas during low temperature period in winter and spring. The results showed that the effect of maintaining temperature and increasing humidity of light conversion film was slightly better than ordinary film. From January to March, compared with open-air tea garden, average temperature of greenhouse increased by 2.8-3.4℃,3.1-3.9℃,1.3-1.9℃, average humidity was higher than open-air tea garden by 5.0-10.4 percent. Compared with open-air tea garden, light intensity of greenhouse decreased by 7.9%-30.2%, the transmittance of light conversion film was slightly lower than ordinary film, but the net photosynthetic rate, stomatal conductance, transpiration rate of tea tree in greenhouse covered with light conversion film were significantly higher than those in ordinary film greenhouse, slightly lower than those in open-air tea garden. Light conversion film combined with CO_2 supplement could significantly increase photosynthesis of tea tree and tea production. In light conversion film greenhouse, tea shoots sprout stage, spring tea start picking period were earlier than ordinary film greenhouse tea garden by 6-7 days, earlier than the open-air tea garden by 23-27 days; compared with open-air tea garden, yield of Mingqian tea (means tea produced before Ching Ming Festival) increased by 51.2%-56.2%, spring tea yield increased by 33.3%, it overcome the defects of covering film solely resulted spring tea production declined in past. Greenhouse tea garden covered with film during cold period in winter and spring had no adversely effect on annual tea production. Tea garden covered with light conversion film was conducive to carbon assimilation, water extract, polyphenols, soluble sugar content of tea increasing, so promoted strength and sweetness of tea soup. After covering light conversion film, climate change could inhibit reproduction of tea leafhopper (Empoasca vitis Gothe) and tea aphid (Toxoptera aurantii Boyer).