Abstract: Aimed at high humidity，low temperature，and many other problems during process of cultivation of flue-cured tobacco floating seedling system in Zunyi region of Guizhou province，moisture content，changing rule of relative humidity in floating seedling establishment in space electric field and differences between control groups were monitored.Combined with change of crop growth and physiological metabolism，relationship between air moisture content，relative humidity and facility heat preservation and growth rate of tobacco seedling in space electric field environment were scientifically analyzed.Results showed that spatial electric field produced by greenhouse electric defogging health promotion and disease prevention system had a strong effect on defogging and reducing air moisture content.Decrease number was more than 40%，number of shutter ventilation was significantly reduced，difference in temperature swings was reduced，0.5～2 ℃ temperature advantage was kept，and seedling time was shortened by 5 d.