icroclimate inside Chinese solar greenhouse is important for crop production and quality.This research focuses on humidity in canopy of plants based on field experiments and data analysis by models of a typical Chinese solar greenhouse in north-east of China.Daily humidity variations inside greenhouse and canopy of plants were measured at different biomass conditions by field experiment.A humidity prediction model of greenhouse is established including external weather conditions and natural ventilation.In addition, a dew formation of canopy is also set up to simulate the humidity of canopy.Compared the numerical results with experimental data, model simulations are proved with success.It shows that the temperature and humidity variations are different under different biomass in winter.Results from the studies indicate that the natural ventilating reduced the humidity content and dew formation of canopy, but the temperature dropped.As expected, to control and assess the effects on the humidity of plant in greenhouse are depending not only by the ventilation but also by the plant biomass cultivated in greenhouse.