Abstract: The effect of weak light, sub low temperature and their co-operation on the seeding of 16 cucumber strains had been studied. The results were as followes: the low light, sub-low temperature and weak light had no obvious effect on the PSⅡ, whereas there was distinctive difference on the chlorophyll fluorescence index M peak and qN among various ecotype. Weak light is the main factor that influenced the growth of cucumber when the co-operation of weak light and sub-low temperature occurred. Under weak light (60～80 μmolm^-2·s^-1), sub-low temperature and weak light co-operation(20℃/12℃), the growth of leaf area was all consistent with the endurance to weak light and low temperature among all the cucumber strains. So the best target to evaluate the endurance to weak light and low temperature is leaf area compared with other physical indexes, and the best treatment-star stage is that the cotyledon fully opened.