Abstract: Based on microclimate observations and the experiments of applying CO₂ into the greenhouses, an improved CO₂ application technique on the amount,time and method was established.An economical decision equation of applying ＣO₂ air fertilizer was also advanced.A technical system that collects the CO₂ from the industrial exhaust gas, transports it by high pressure,and applies it to greenhouse was promoted.It is an effective way to decrease industry pollut,compensate CO₂ in greenhouse,increase yield and guality of greenhouse vegetable.