Taking 4 different cucumber varieties as material，this study tested chlorophyll content changes
in cucumber leaves under different low light treatments，explored the most appropriate light intensity and best
appraisal period for low light tolerance identification during cucumber seedling stage，and at the same time，
the low light tolerance identification was conducted. Beside，this paper analyzed the reduction rate of leaves
chlorophyll content during cucumber seedling stage，and the reduction rate of fruit yield in adult stage，and
also the reduction ratio of plant dry weight. The paper explored the correlation between cucumber tolerance to
low light in seedling stage and adult plant stage. The results showed that the reduction rate of leaves chlorophyll
content during seedling stage under 20 mol·m^-2·s^-1 light stress at 20 days could be used as indicator for rapid
identification of low light tolerance. The reduction rates of both fruit yield in adult stage and plant dry weight could
reflect the differences in low light tolerance between varieties during adult stage. There existed a significant positive
correlation between leaves chlorophyll content reduction rate in seedling stage and fruit yield reduction rate in adult
stage. Low light tolerance in seedling and adult stages of different varieties was the same. _W25 had strong tolerance
to low light，and W₅ had poor tolerance to low light.