Tea plant (Camellia sinensis) cultivation has a long history in China. The range of optimum growth temperature of tea is considered to be between 20℃ and 30℃. Significant decrease in temperature during a cold wave can harm tea plantations. Cold stress is a major abiotic factor that affects photosynthesis, respiration, transpiration, and some other physiological processes such as antioxidant enzymatic activity. Previous studies have evaluated stress tolerance of plants using photosynthetic parameters, chlorophyll fluorescence parameters, and antioxidant enzymatic activity. Effects of cold stress on physiological and biochemical indices, as well as on photosynthetic parameters have been studied under environmentally controlled conditions. The objective of this study was to investigate the effect of cold wave on the photosynthetic parameters and antioxidant enzymatic activity in four green tea varieties, Longjing No.43, Jiukeng, Wuniuzao, and Fortin white tea under field conditions in 2013. Data on the daily temperature (minimum, maximum, and mean), daily relative humidity (minimum, maximum, and mean), and daily solar radiation were collected to identify the most important factor that affects the tea plant during the cold wave. The mean daily temperature was significantly reduced from November 23 to 25, reached the lowest value on Nov 28, and then began to rise. The total chlorophyll content, photosynthetic rate (P_max), apparent quantum yield (AQY), PSⅡ photochemical efficiency (Fv/Fm), and non-photochemical quenching (qN) of all four tea varieties were initially decreased and then increased from November 23 to December 5. Fotin had the maximum values of chlorophyll content, P_max, AQY, and Fv/Fm. Wuniuzao had the minimum mean value of qN. Jiukeng had the maximum mean value of peroxidase (POD) activity that increased continuously from November 23 to December 5, while Longjing No.43 and Fortin had the minimum values of POD activity. Stomatal limiting value (Ls) and malondialdehyde (MDA) contents increased initially and then decreased from November 23 to December 5; Longjing No.43 had the maximum mean value of MDA, while Fortin had the minimum mean value. The total chlorophyll content, P_max, AQY, Fv/Fm, and qN were positively correlated with the minimum daily temperature, while Ls and POD activity were negatively correlated with the minimum daily mean temperature. The minimum daily mean temperature was the abiotic factor that had the most significant effect on the photosynthetic parameters and antioxidant enzymatic activity in all four tea varieties. Principal component analysis (PCA) provided a quantitative evaluation of photosynthetic parameters, fluorescence parameters, and antioxidant enzymatic activity under cold stress conditions. PCA showed that MDA content, Fv/Fm, and POD activity were the main factors that affected the biological activity in all four tea varieties. Cold tolerance evaluation index of Fortin and Longjing No.43 was the highest (8.38) and the lowest (-6.88), respectively. Both Wuniuzao and Jiukeng had moderate cold tolerance evaluation indices and the latter was less cold tolerant that the former. In response to cold stress, plants, including tea, have diverse mechanisms that allow them to mitigate and adjust to cold environmental conditions.