Taking watermelon（Citrullus lanatus L.） variety ‘Qingfeng’ as experimental material，this
paper studied the effect of light quality on watermelon seedling growth and photosynthetic characteristics under
conditions of artificial-light plant factory，and investigated high efficient artificial-light quality environment
for improving seedling quality and shortening nursing seedling period．The results showed that comparing with
the traditional light source fluorescent lamp（CK），the light quality 5R/4B/1Y （red light 150 μmol·m^-2·s^-1，
blue light 120 μmol·m^-2·s^-1，yellow light 30 μmol·m^-2·s^-1） had better advantage for nursing seedling．Under
5R/4B/1Y treatment the watermelon seedling was stumpish with thick stem．The chlorophyll content，net
photosynthetic rate and the strong seedling index were significantly higher than that of the CK．So，5R/4B/1Y
can be recommended as a better light quality recipe for artificial-light nursing seedling of watermelon.