Abstract: The effects of space electric field on absorption of CO₂ and growth speed of plants were studied. First，the ability of absorbing CO₂ and ¹⁴C—HCO^-₃ for tomato planted in nutrient solution under different space electric-field conditions was analyzed by isotope tracer method. It is proved that ¹⁴C—HCO^-₃ is a kind of anion controlled by space electric field. The flow direction of ¹⁴C—HCO^-₃ changes with space electric field strength. Taking hollow vegetable as test material, a growth-comparison test was performed by combination of the parameters of space electric field and initial concentration of CO₂. The result analyzed by CO₂ analytical method of infrared ray shows that polarity of electric field has remarkable influences on CO₂ absorption rate of plant. The positive pole of electric field can greatly improve CO₂ absorption, it can increase the growth speed and double the production of plant by a big margin in greenhouse. The research lays a foundation for further study of increasing plant growth by space electric field.