Abstract: [Objective][Method]To control the environment factors and set artificial light scheme reasonably in multi-span plastic greenhouse used for tobacco seedling, basing on the different growth period environment need of flue-cured tobacco seedlings, the inside and outside environment factors and the light intensity change between seedling frame layers were tested and analyzed in Guizhou typical tobacco floating seedling plastic greenhouse. [Result]The result show, the highest temperature can reach 25 ℃ in sunny day, but in cloudy day, it is only 15.3 ℃, the relative humidity changed from 40 % to 90 %, and the light intensity range was 50 to 5000 umol.m-2.s-1, which are fit to tobacco seedling growth. When using the three-dimensional seedling frame with 6 layers, the natural light on the fifth and sixth layer is enough for seedling growth, but the artificial light was need to be added from the first to the fourth layer. [Conclusion]This experiment research can give theoretical proof for reasonable environment adjust measures and artificial light scheme.