The chlorophyII fluorescence parameters of leaves of 5 tea-plant cultivars (lines) were measured by the portable modulated chlorophyll fluorometer (PAM-2500) in spring, summer and autumn, and the differences of the parameters between seasons or inter-cultivars (lines) were analyzed then. The results showed that tea-plant could change the proportion of Y (NPQ) and Y (NO) by the self-regulation mechanism to adapt the climate change, but the adaptability was different among different cultivars (lines). The 0311 and 0305 behaved the best in the 5 tested cultivars (lines), their electron transport rate of PSII, start speed of photochemical reaction and minimum saturation intensity were maintained a high level. And the results also indicated that the 0311 and 0305 could have strong light energy utilization efficiency, big potential physiological and biochemical foundations to obtain high biomass and a high adaptability to the climate.