Abstract: Based on the five years observation data in self-controlled greenhouse at Donghai vegetable demonstration base in Shanghai,and adopting mathematical statistics methods,this paper analyzed the monthly variation characteristics of ambient illumination,temperature and CO₂ concentration during wintertime,disclosed the persisting hours of favorable and unfavorable illumination grade under different weather conditions,appearing cases of different threshold air temperature,persisting hours and characteristics of CO₂ shortfall,and variation characteristics of air relative humidity.The correlation equations between daytime average air temperature,CO₂ concentration,relative humidity and illumination in greenhouse were set up,the main problems in self-controlled greenhouse during wintertime were pointed out,and some related modulate advises were put forward.In Shanghai area,the key points of obtaining high yields in greenhouse during wintertime should be to insure sufficient illumination,modulate air temperature at nights,raise forenoon air temperature in sunny days,and enlarge air temperature difference between daytime and night to increase net photosynthesis matters.